21285708 has 24 divisors (see below), whose sum is σ = 50061312. Its totient is φ = 7038864.

The previous prime is 21285703. The next prime is 21285709. The reversal of 21285708 is 80758212.

It is a super-2 number, since 2×21285708² = 906162730122528, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21285703) by changing a digit.

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, 5460 + ... + 8507.

It is an arithmetic number, because the mean of its divisors is an integer number (2085888).

Almost surely, 2^21285708 is an apocalyptic number.

It is an amenable number.

21285708 is an abundant number, since it is smaller than the sum of its proper divisors (28775604).

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

21285708 is a wasteful number, since it uses less digits than its factorization.

21285708 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14101 (or 14099 counting only the distinct ones).

The product of its (nonzero) digits is 8960, while the sum is 33.

The square root of 21285708 is about 4613.6436793493. The cubic root of 21285708 is about 277.1379712078.

The spelling of 21285708 in words is "twenty-one million, two hundred eighty-five thousand, seven hundred eight".