21153964 has 12 divisors (see below), whose sum is σ = 39867184. Its totient is φ = 9763344.

The previous prime is 21153959. The next prime is 21153971. The reversal of 21153964 is 46935112.

It is a hoax number, since the sum of its digits (31) coincides with the sum of the digits of its distinct prime factors.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 203352 + ... + 203455.

Almost surely, 2^21153964 is an apocalyptic number.

It is an amenable number.

21153964 is a deficient number, since it is larger than the sum of its proper divisors (18713220).

21153964 is a wasteful number, since it uses less digits than its factorization.

21153964 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 406824 (or 406822 counting only the distinct ones).

The product of its digits is 6480, while the sum is 31.

The square root of 21153964 is about 4599.3438662488. The cubic root of 21153964 is about 276.5650225801.

The spelling of 21153964 in words is "twenty-one million, one hundred fifty-three thousand, nine hundred sixty-four".