21920756 has 48 divisors (see below), whose sum is σ = 47463360. Its totient is φ = 8709120.

The previous prime is 21920749. The next prime is 21920791. The reversal of 21920756 is 65702912.

It is a super-2 number, since 2×21920756² = 961039087223072, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9860 + ... + 11876.

It is an arithmetic number, because the mean of its divisors is an integer number (988820).

Almost surely, 2^21920756 is an apocalyptic number.

21920756 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

21920756 is an abundant number, since it is smaller than the sum of its proper divisors (25542604).

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

21920756 is a wasteful number, since it uses less digits than its factorization.

21920756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2064 (or 2062 counting only the distinct ones).

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 21920756 is about 4681.9607003904. The cubic root of 21920756 is about 279.8670967908.

The spelling of 21920756 in words is "twenty-one million, nine hundred twenty thousand, seven hundred fifty-six".