21957937 has 4 divisors (see below), whose sum is σ = 22054896. Its totient is φ = 21860980.

The previous prime is 21957917. The next prime is 21957961. The reversal of 21957937 is 73975912.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21957937 - 2⁷ = 21957809 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21957893 and 21957902.

It is not an unprimeable number, because it can be changed into a prime (21957917) 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, 48139 + ... + 48592.

It is an arithmetic number, because the mean of its divisors is an integer number (5513724).

Almost surely, 2^21957937 is an apocalyptic number.

It is an amenable number.

21957937 is a deficient number, since it is larger than the sum of its proper divisors (96959).

21957937 is an equidigital number, since it uses as much as digits as its factorization.

21957937 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96958.

The product of its digits is 119070, while the sum is 43.

The square root of 21957937 is about 4685.9296836380. The cubic root of 21957937 is about 280.0252400717.

It can be divided in two parts, 219 and 57937, that multiplied together give a triangular number (12688203 = T₅₀₃₇).

The spelling of 21957937 in words is "twenty-one million, nine hundred fifty-seven thousand, nine hundred thirty-seven".