21522996 has 126 divisors (see below), whose sum is σ = 63090146. Its totient is φ = 6415200.

The previous prime is 21522989. The next prime is 21523001. The reversal of 21522996 is 69922512.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 12702096 + 8820900 = 3564^2 + 2970^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nialpdrome in base 3 and base 9.

It is a zygodrome in base 3 and base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 21522996.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 41 ways as a sum of consecutive naturals, for example, 352806 + ... + 352866.

Almost surely, 2^21522996 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21522996, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31545073).

21522996 is an abundant number, since it is smaller than the sum of its proper divisors (41567150).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21522996 is a wasteful number, since it uses less digits than its factorization.

21522996 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 105 (or 77 counting only the distinct ones).

The product of its digits is 19440, while the sum is 36.

The square root of 21522996 is about 4639.2883074886. The cubic root of 21522996 is about 278.1639906789.

The spelling of 21522996 in words is "twenty-one million, five hundred twenty-two thousand, nine hundred ninety-six".