21086868 has 48 divisors (see below), whose sum is σ = 56839104. Its totient is φ = 6013440.

The previous prime is 21086861. The next prime is 21086887. The reversal of 21086868 is 86868012.

21086868 is a modest number, since divided by 6868 gives 2108 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21086861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2455 + ... + 6942.

It is an arithmetic number, because the mean of its divisors is an integer number (1184148).

Almost surely, 2^21086868 is an apocalyptic number.

It is an amenable number.

21086868 is an abundant number, since it is smaller than the sum of its proper divisors (35752236).

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

21086868 is a wasteful number, since it uses less digits than its factorization.

21086868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9432 (or 9430 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 39.

The square root of 21086868 is about 4592.0439893363. The cubic root of 21086868 is about 276.2723105313.

It can be divided in two parts, 210 and 86868, that added together give a palindrome (87078).

The spelling of 21086868 in words is "twenty-one million, eighty-six thousand, eight hundred sixty-eight".