21957792 has 48 divisors (see below), whose sum is σ = 58125312. Its totient is φ = 7257600.

The previous prime is 21957781. The next prime is 21957799. The reversal of 21957792 is 29775912.

It is a tau number, because it is divible by the number of its divisors (48).

It is not an unprimeable number, because it can be changed into a prime (21957799) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 11292 + ... + 13092.

It is an arithmetic number, because the mean of its divisors is an integer number (1210944).

Almost surely, 2^21957792 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21957792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29062656).

21957792 is an abundant number, since it is smaller than the sum of its proper divisors (36167520).

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

21957792 is a wasteful number, since it uses less digits than its factorization.

21957792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1941 (or 1933 counting only the distinct ones).

The product of its digits is 79380, while the sum is 42.

The square root of 21957792 is about 4685.9142117627. The cubic root of 21957792 is about 280.0246236848.

The spelling of 21957792 in words is "twenty-one million, nine hundred fifty-seven thousand, seven hundred ninety-two".