639875851 has 2 divisors, whose sum is σ = 639875852. Its totient is φ = 639875850.

The previous prime is 639875843. The next prime is 639875921. The reversal of 639875851 is 158578936.

639875851 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639875851 - 2³ = 639875843 is a prime.

It is a super-2 number, since 2×639875851² = 818882209385948402, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (639875051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319937925 + 319937926.

It is an arithmetic number, because the mean of its divisors is an integer number (319937926).

Almost surely, 2^639875851 is an apocalyptic number.

639875851 is a deficient number, since it is larger than the sum of its proper divisors (1).

639875851 is an equidigital number, since it uses as much as digits as its factorization.

639875851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1814400, while the sum is 52.

The square root of 639875851 is about 25295.7674522834. The cubic root of 639875851 is about 861.7181493025.

The spelling of 639875851 in words is "six hundred thirty-nine million, eight hundred seventy-five thousand, eight hundred fifty-one".