21306765741571 has 2 divisors, whose sum is σ = 21306765741572. Its totient is φ = 21306765741570.

The previous prime is 21306765741553. The next prime is 21306765741629. The reversal of 21306765741571 is 17514756760312.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21306765741571 - 2⁹ = 21306765741059 is a prime.

It is not a weakly prime, because it can be changed into another prime (21306765741511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10653382870785 + 10653382870786.

It is an arithmetic number, because the mean of its divisors is an integer number (10653382870786).

Almost surely, 2^{21306765741571} is an apocalyptic number.

21306765741571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21306765741571 is an equidigital number, since it uses as much as digits as its factorization.

21306765741571 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7408800, while the sum is 55.

The spelling of 21306765741571 in words is "twenty-one trillion, three hundred six billion, seven hundred sixty-five million, seven hundred forty-one thousand, five hundred seventy-one".