21975120 has 120 divisors (see below), whose sum is σ = 77066496. Its totient is φ = 5601024.

The previous prime is 21975113. The next prime is 21975131. The reversal of 21975120 is 2157912.

It is a tau number, because it is divible by the number of its divisors (120).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 15897 + ... + 17223.

Almost surely, 2^21975120 is an apocalyptic number.

21975120 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 21975120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38533248).

21975120 is an abundant number, since it is smaller than the sum of its proper divisors (55091376).

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

21975120 is a wasteful number, since it uses less digits than its factorization.

21975120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1369 (or 1360 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 21975120 is about 4687.7627926336. The cubic root of 21975120 is about 280.0982648301.

The spelling of 21975120 in words is "twenty-one million, nine hundred seventy-five thousand, one hundred twenty".