642508331 has 2 divisors, whose sum is σ = 642508332. Its totient is φ = 642508330.

The previous prime is 642508231. The next prime is 642508337. The reversal of 642508331 is 133805246.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 642508331 - 2²⁶ = 575399467 is a prime.

It is a super-2 number, since 2×642508331² = 825633910808811122, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (642508337) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321254165 + 321254166.

It is an arithmetic number, because the mean of its divisors is an integer number (321254166).

Almost surely, 2^642508331 is an apocalyptic number.

642508331 is a deficient number, since it is larger than the sum of its proper divisors (1).

642508331 is an equidigital number, since it uses as much as digits as its factorization.

642508331 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 642508331 is about 25347.7480459310. The cubic root of 642508331 is about 862.8982490752.

The spelling of 642508331 in words is "six hundred forty-two million, five hundred eight thousand, three hundred thirty-one".