21879120 has 40 divisors (see below), whose sum is σ = 67826016. Its totient is φ = 5834368.

The previous prime is 21879103. The next prime is 21879139. The reversal of 21879120 is 2197812.

It is a tau number, because it is divible by the number of its divisors (40).

It is a hoax number, since the sum of its digits (30) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 45342 + ... + 45821.

Almost surely, 2^21879120 is an apocalyptic number.

21879120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21879120 is an abundant number, since it is smaller than the sum of its proper divisors (45946896).

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

21879120 is a wasteful number, since it uses less digits than its factorization.

21879120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91179 (or 91173 counting only the distinct ones).

The product of its (nonzero) digits is 2016, while the sum is 30.

The square root of 21879120 is about 4677.5121592573. The cubic root of 21879120 is about 279.6897925075.

The spelling of 21879120 in words is "twenty-one million, eight hundred seventy-nine thousand, one hundred twenty".