21326864 has 20 divisors (see below), whose sum is σ = 44499756. Its totient is φ = 9843072.

The previous prime is 21326863. The next prime is 21326897. The reversal of 21326864 is 46862312.

It can be written as a sum of positive squares in 2 ways, for example, as 5326864 + 16000000 = 2308^2 + 4000^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21326864.

It is not an unprimeable number, because it can be changed into a prime (21326863) 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, 51059 + ... + 51474.

Almost surely, 2^21326864 is an apocalyptic number.

It is an amenable number.

21326864 is an abundant number, since it is smaller than the sum of its proper divisors (23172892).

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

21326864 is a wasteful number, since it uses less digits than its factorization.

21326864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 102554 (or 102548 counting only the distinct ones).

The product of its digits is 13824, while the sum is 32.

The square root of 21326864 is about 4618.1017745390. The cubic root of 21326864 is about 277.3164719984.

The spelling of 21326864 in words is "twenty-one million, three hundred twenty-six thousand, eight hundred sixty-four".