21322761 has 16 divisors (see below), whose sum is σ = 29621760. Its totient is φ = 13628160.

The previous prime is 21322757. The next prime is 21322781. The reversal of 21322761 is 16722312.

It is not a de Polignac number, because 21322761 - 2² = 21322757 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21322781) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9495 + ... + 11523.

It is an arithmetic number, because the mean of its divisors is an integer number (1851360).

Almost surely, 2^21322761 is an apocalyptic number.

It is an amenable number.

21322761 is a deficient number, since it is larger than the sum of its proper divisors (8298999).

21322761 is a wasteful number, since it uses less digits than its factorization.

21322761 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2176.

The product of its digits is 1008, while the sum is 24.

The square root of 21322761 is about 4617.6575230305. The cubic root of 21322761 is about 277.2986868791.

The spelling of 21322761 in words is "twenty-one million, three hundred twenty-two thousand, seven hundred sixty-one".