642508231 has 2 divisors, whose sum is σ = 642508232. Its totient is φ = 642508230.

The previous prime is 642508157. The next prime is 642508331. The reversal of 642508231 is 132805246.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 642508231 - 2¹³ = 642500039 is a prime.

It is a super-2 number, since 2×642508231² = 825633653805498722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 642508193 and 642508202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (642508331) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 321254115 + 321254116.

It is an arithmetic number, because the mean of its divisors is an integer number (321254116).

Almost surely, 2^642508231 is an apocalyptic number.

642508231 is a deficient number, since it is larger than the sum of its proper divisors (1).

642508231 is an equidigital number, since it uses as much as digits as its factorization.

642508231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 11520, while the sum is 31.

The square root of 642508231 is about 25347.7460733691. The cubic root of 642508231 is about 862.8982043080.

The spelling of 642508231 in words is "six hundred forty-two million, five hundred eight thousand, two hundred thirty-one".