21892957 has 4 divisors (see below), whose sum is σ = 23180796. Its totient is φ = 20605120.

The previous prime is 21892939. The next prime is 21892963. The reversal of 21892957 is 75929812.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10830681 + 11062276 = 3291^2 + 3326^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21892957 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21892907) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 643894 + ... + 643927.

It is an arithmetic number, because the mean of its divisors is an integer number (5795199).

Almost surely, 2^21892957 is an apocalyptic number.

It is an amenable number.

21892957 is a deficient number, since it is larger than the sum of its proper divisors (1287839).

21892957 is a wasteful number, since it uses less digits than its factorization.

21892957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1287838.

The product of its digits is 90720, while the sum is 43.

The square root of 21892957 is about 4678.9910237144. The cubic root of 21892957 is about 279.7487414368.

The spelling of 21892957 in words is "twenty-one million, eight hundred ninety-two thousand, nine hundred fifty-seven".