639875843 has 2 divisors, whose sum is σ = 639875844. Its totient is φ = 639875842.

The previous prime is 639875839. The next prime is 639875851. The reversal of 639875843 is 348578936.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639875843 - 2² = 639875839 is a prime.

It is not a weakly prime, because it can be changed into another prime (639875443) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319937921 + 319937922.

It is an arithmetic number, because the mean of its divisors is an integer number (319937922).

Almost surely, 2^639875843 is an apocalyptic number.

639875843 is a deficient number, since it is larger than the sum of its proper divisors (1).

639875843 is an equidigital number, since it uses as much as digits as its factorization.

639875843 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4354560, while the sum is 53.

The square root of 639875843 is about 25295.7672941542. The cubic root of 639875843 is about 861.7181457113.

The spelling of 639875843 in words is "six hundred thirty-nine million, eight hundred seventy-five thousand, eight hundred forty-three".