In number theory, an abundant number or excessive number is a positive integer for which the sum of its proper divisors is greater than the number. The...

In number theory, a colossally abundant number (sometimes abbreviated as CA) is a natural number that, in a particular, rigorous sense, has many divisors...

In number theory, a highly abundant number is a natural number with the property that the sum of its divisors (including itself) is greater than the sum...

primitive abundant number is an abundant number whose proper divisors are all deficient numbers. For example, 20 is a primitive abundant number because:...

twentieth abundant and highly abundant number (with 20 the first primitive abundant number and 70 the second). 90 is the third unitary perfect number (after...

natural number following 199 and preceding 201. 200 is an abundant number, as 265, the sum of its proper divisors, is greater than itself. The number appears...

number (7 × 11 × 13), pentagonal number, pentatope number, palindromic number 1002 = sphenic number, Mertens function zero, abundant number, number of...

whereas an abundant number has a sum of its proper divisors that is larger than the number itself. Primitive abundant numbers are abundant numbers whose...

the prime 7-aliquot tree. It is the smallest primitive abundant number, and the first number to have an abundance of 2, followed by 104. 20 is the length...

semiperfect number. Eighteen is the first inverted square-prime of the form p·q2. In base ten, it is a Harshad number. It is an abundant number, as the sum...