21685914 has 32 divisors (see below), whose sum is σ = 51027840. Its totient is φ = 6803136.

The previous prime is 21685913. The next prime is 21685967. The reversal of 21685914 is 41958612.

21685914 is a `hidden beast` number, since 2 + 1 + 68 + 591 + 4 = 666.

It is not an unprimeable number, because it can be changed into a prime (21685913) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10894 + ... + 12729.

It is an arithmetic number, because the mean of its divisors is an integer number (1594620).

Almost surely, 2^21685914 is an apocalyptic number.

21685914 is an abundant number, since it is smaller than the sum of its proper divisors (29341926).

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

21685914 is a wasteful number, since it uses less digits than its factorization.

21685914 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23651 (or 23645 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The square root of 21685914 is about 4656.8137175541. The cubic root of 21685914 is about 278.8640799388.

The spelling of 21685914 in words is "twenty-one million, six hundred eighty-five thousand, nine hundred fourteen".