643716020971 has 2 divisors, whose sum is σ = 643716020972. Its totient is φ = 643716020970.

The previous prime is 643716020933. The next prime is 643716021019. The reversal of 643716020971 is 179020617346.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-643716020971 is a prime.

It is not a weakly prime, because it can be changed into another prime (643716020921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321858010485 + 321858010486.

It is an arithmetic number, because the mean of its divisors is an integer number (321858010486).

Almost surely, 2^643716020971 is an apocalyptic number.

643716020971 is a deficient number, since it is larger than the sum of its proper divisors (1).

643716020971 is an equidigital number, since it uses as much as digits as its factorization.

643716020971 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 381024, while the sum is 46.

The spelling of 643716020971 in words is "six hundred forty-three billion, seven hundred sixteen million, twenty thousand, nine hundred seventy-one".