21642565337 has 2 divisors, whose sum is σ = 21642565338. Its totient is φ = 21642565336.

The previous prime is 21642565331. The next prime is 21642565379. The reversal of 21642565337 is 73356524612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21228198601 + 414366736 = 145699^2 + 20356^2 .

It is a cyclic number.

It is not a de Polignac number, because 21642565337 - 2²⁰ = 21641516761 is a prime.

It is not a weakly prime, because it can be changed into another prime (21642565331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10821282668 + 10821282669.

It is an arithmetic number, because the mean of its divisors is an integer number (10821282669).

Almost surely, 2^21642565337 is an apocalyptic number.

It is an amenable number.

21642565337 is a deficient number, since it is larger than the sum of its proper divisors (1).

21642565337 is an equidigital number, since it uses as much as digits as its factorization.

21642565337 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 907200, while the sum is 44.

The spelling of 21642565337 in words is "twenty-one billion, six hundred forty-two million, five hundred sixty-five thousand, three hundred thirty-seven".