21521696 has 24 divisors (see below), whose sum is σ = 48424320. Its totient is φ = 9223488.

The previous prime is 21521693. The next prime is 21521701. The reversal of 21521696 is 69612512.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (32).

It is not an unprimeable number, because it can be changed into a prime (21521693) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 47816 + ... + 48263.

It is an arithmetic number, because the mean of its divisors is an integer number (2017680).

Almost surely, 2^21521696 is an apocalyptic number.

It is an amenable number.

21521696 is an abundant number, since it is smaller than the sum of its proper divisors (26902624).

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

21521696 is an equidigital number, since it uses as much as digits as its factorization.

21521696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96096 (or 96088 counting only the distinct ones).

The product of its digits is 6480, while the sum is 32.

The square root of 21521696 is about 4639.1481976759. The cubic root of 21521696 is about 278.1583901502.

The spelling of 21521696 in words is "twenty-one million, five hundred twenty-one thousand, six hundred ninety-six".