21870900 has 108 divisors (see below), whose sum is σ = 72217600. Its totient is φ = 5520960.

The previous prime is 21870883. The next prime is 21870931. The reversal of 21870900 is 907812.

It is a congruent number.

It is an unprimeable number.

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 35 ways as a sum of consecutive naturals, for example, 16461 + ... + 17739.

Almost surely, 2^21870900 is an apocalyptic number.

21870900 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21870900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36108800).

21870900 is an abundant number, since it is smaller than the sum of its proper divisors (50346700).

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

21870900 is a wasteful number, since it uses less digits than its factorization.

21870900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1318 (or 1308 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 21870900 is about 4676.6334044909. The cubic root of 21870900 is about 279.6547615727.

It can be divided in two parts, 21870 and 900, that multiplied together give a cube (19683000 = 270³).

The spelling of 21870900 in words is "twenty-one million, eight hundred seventy thousand, nine hundred".