21507696 has 120 divisors (see below), whose sum is σ = 72475520. Its totient is φ = 5816448.

The previous prime is 21507667. The next prime is 21507701. The reversal of 21507696 is 69670512.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21507696.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 18591 + ... + 19713.

Almost surely, 2^21507696 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 21507696, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36237760).

21507696 is an abundant number, since it is smaller than the sum of its proper divisors (50967824).

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

21507696 is a wasteful number, since it uses less digits than its factorization.

21507696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1163 (or 1154 counting only the distinct ones).

The product of its (nonzero) digits is 22680, while the sum is 36.

The square root of 21507696 is about 4637.6390545190. The cubic root of 21507696 is about 278.0980624670.

The spelling of 21507696 in words is "twenty-one million, five hundred seven thousand, six hundred ninety-six".