21086875 has 10 divisors (see below), whose sum is σ = 26350940. Its totient is φ = 16869000.

The previous prime is 21086861. The next prime is 21086887. The reversal of 21086875 is 57868012.

It is a de Polignac number, because none of the positive numbers 2^k-21086875 is a prime.

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 9 ways as a sum of consecutive naturals, for example, 16245 + ... + 17494.

It is an arithmetic number, because the mean of its divisors is an integer number (2635094).

Almost surely, 2^21086875 is an apocalyptic number.

21086875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21086875 is a deficient number, since it is larger than the sum of its proper divisors (5264065).

21086875 is an frugal number, since it uses more digits than its factorization.

21086875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33759 (or 33744 counting only the distinct ones).

The product of its (nonzero) digits is 26880, while the sum is 37.

The square root of 21086875 is about 4592.0447515241. The cubic root of 21086875 is about 276.2723411018.

The spelling of 21086875 in words is "twenty-one million, eighty-six thousand, eight hundred seventy-five".