21870975 has 24 divisors (see below), whose sum is σ = 41326720. Its totient is φ = 9997920.

The previous prime is 21870973. The next prime is 21870977. The reversal of 21870975 is 57907812.

It is an interprime number because it is at equal distance from previous prime (21870973) and next prime (21870977).

It is not a de Polignac number, because 21870975 - 2¹ = 21870973 is a prime.

It is a plaindrome in base 8.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21870971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 20305 + ... + 21354.

Almost surely, 2^21870975 is an apocalyptic number.

21870975 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21870975 is a deficient number, since it is larger than the sum of its proper divisors (19455745).

21870975 is a wasteful number, since it uses less digits than its factorization.

21870975 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 41679 (or 41674 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 39.

The square root of 21870975 is about 4676.6414230728. The cubic root of 21870975 is about 279.6550812377.

The spelling of 21870975 in words is "twenty-one million, eight hundred seventy thousand, nine hundred seventy-five".