639531371 has 2 divisors, whose sum is σ = 639531372. Its totient is φ = 639531370.

The previous prime is 639531367. The next prime is 639531391. The reversal of 639531371 is 173135936.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 639531371 - 2² = 639531367 is a prime.

It is a super-3 number, since 3×639531371³ (a number of 27 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (639531301) 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, 319765685 + 319765686.

It is an arithmetic number, because the mean of its divisors is an integer number (319765686).

Almost surely, 2^639531371 is an apocalyptic number.

639531371 is a deficient number, since it is larger than the sum of its proper divisors (1).

639531371 is an equidigital number, since it uses as much as digits as its factorization.

639531371 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51030, while the sum is 38.

The square root of 639531371 is about 25288.9574913637. The cubic root of 639531371 is about 861.5634849497.

The spelling of 639531371 in words is "six hundred thirty-nine million, five hundred thirty-one thousand, three hundred seventy-one".