642636959 has 2 divisors, whose sum is σ = 642636960. Its totient is φ = 642636958.

The previous prime is 642636937. The next prime is 642636977. The reversal of 642636959 is 959636246.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-642636959 is a prime.

It is a super-2 number, since 2×642636959² = 825964522145535362, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642636919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321318479 + 321318480.

It is an arithmetic number, because the mean of its divisors is an integer number (321318480).

Almost surely, 2^642636959 is an apocalyptic number.

642636959 is a deficient number, since it is larger than the sum of its proper divisors (1).

642636959 is an equidigital number, since it uses as much as digits as its factorization.

642636959 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2099520, while the sum is 50.

The square root of 642636959 is about 25350.2851857726. The cubic root of 642636959 is about 862.9558283390.

The spelling of 642636959 in words is "six hundred forty-two million, six hundred thirty-six thousand, nine hundred fifty-nine".