642664039571 has 2 divisors, whose sum is σ = 642664039572. Its totient is φ = 642664039570.

The previous prime is 642664039499. The next prime is 642664039601. The reversal of 642664039571 is 175930466246.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 642664039571 - 2¹⁰ = 642664038547 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (642664539571) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321332019785 + 321332019786.

It is an arithmetic number, because the mean of its divisors is an integer number (321332019786).

Almost surely, 2^642664039571 is an apocalyptic number.

642664039571 is a deficient number, since it is larger than the sum of its proper divisors (1).

642664039571 is an equidigital number, since it uses as much as digits as its factorization.

642664039571 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6531840, while the sum is 53.

The spelling of 642664039571 in words is "six hundred forty-two billion, six hundred sixty-four million, thirty-nine thousand, five hundred seventy-one".