21706864 has 30 divisors (see below), whose sum is σ = 43268064. Its totient is φ = 10549440.

The previous prime is 21706837. The next prime is 21706889. The reversal of 21706864 is 46860712.

It is a congruent number.

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 5 ways as a sum of consecutive naturals, for example, 21409 + ... + 22399.

Almost surely, 2^21706864 is an apocalyptic number.

It is an amenable number.

21706864 is a deficient number, since it is larger than the sum of its proper divisors (21561200).

21706864 is an equidigital number, since it uses as much as digits as its factorization.

21706864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1073 (or 1030 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 21706864 is about 4659.0625666544. The cubic root of 21706864 is about 278.9538513017.

The spelling of 21706864 in words is "twenty-one million, seven hundred six thousand, eight hundred sixty-four".