639157 has 2 divisors, whose sum is σ = 639158. Its totient is φ = 639156.

The previous prime is 639151. The next prime is 639167. The reversal of 639157 is 751936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 417316 + 221841 = 646^2 + 471^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-639157 is a prime.

639157 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319578 + 319579.

It is an arithmetic number, because the mean of its divisors is an integer number (319579).

2⁶³⁹¹⁵⁷ is an apocalyptic number.

It is an amenable number.

639157 is a deficient number, since it is larger than the sum of its proper divisors (1).

639157 is an equidigital number, since it uses as much as digits as its factorization.

639157 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5670, while the sum is 31.

The square root of 639157 is about 799.4729513873. The cubic root of 639157 is about 86.1395337169.

The spelling of 639157 in words is "six hundred thirty-nine thousand, one hundred fifty-seven".