21523628 has 24 divisors (see below), whose sum is σ = 43314432. Its totient is φ = 9167184.

The previous prime is 21523609. The next prime is 21523631. The reversal of 21523628 is 82632512.

It is a self number, because there is not a number n which added to its sum of digits gives 21523628.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2375 + ... + 6977.

It is an arithmetic number, because the mean of its divisors is an integer number (1804768).

Almost surely, 2^21523628 is an apocalyptic number.

21523628 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21523628 is an abundant number, since it is smaller than the sum of its proper divisors (21790804).

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

21523628 is a wasteful number, since it uses less digits than its factorization.

21523628 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4781 (or 4779 counting only the distinct ones).

The product of its digits is 5760, while the sum is 29.

The square root of 21523628 is about 4639.3564208843. The cubic root of 21523628 is about 278.1667133159.

The spelling of 21523628 in words is "twenty-one million, five hundred twenty-three thousand, six hundred twenty-eight".