21660937 has 4 divisors (see below), whose sum is σ = 22121856. Its totient is φ = 21200020.

The previous prime is 21660929. The next prime is 21660953. The reversal of 21660937 is 73906612.

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 21660937 - 2³ = 21660929 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21660967) 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, 230389 + ... + 230482.

It is an arithmetic number, because the mean of its divisors is an integer number (5530464).

Almost surely, 2^21660937 is an apocalyptic number.

It is an amenable number.

21660937 is a deficient number, since it is larger than the sum of its proper divisors (460919).

21660937 is an equidigital number, since it uses as much as digits as its factorization.

21660937 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 460918.

The product of its (nonzero) digits is 13608, while the sum is 34.

The square root of 21660937 is about 4654.1311756331. The cubic root of 21660937 is about 278.7569771759.

The spelling of 21660937 in words is "twenty-one million, six hundred sixty thousand, nine hundred thirty-seven".