21487875 has 16 divisors (see below), whose sum is σ = 35756448. Its totient is φ = 11460000.

The previous prime is 21487783. The next prime is 21487891. The reversal of 21487875 is 57878412.

It is not a de Polignac number, because 21487875 - 2¹² = 21483779 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 15 ways as a sum of consecutive naturals, for example, 28276 + ... + 29025.

It is an arithmetic number, because the mean of its divisors is an integer number (2234778).

Almost surely, 2^21487875 is an apocalyptic number.

21487875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21487875 is a deficient number, since it is larger than the sum of its proper divisors (14268573).

21487875 is an equidigital number, since it uses as much as digits as its factorization.

21487875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57319 (or 57309 counting only the distinct ones).

The product of its digits is 125440, while the sum is 42.

The square root of 21487875 is about 4635.5015909824. The cubic root of 21487875 is about 278.0126066088.

The spelling of 21487875 in words is "twenty-one million, four hundred eighty-seven thousand, eight hundred seventy-five".