639542357 has 2 divisors, whose sum is σ = 639542358. Its totient is φ = 639542356.

The previous prime is 639542339. The next prime is 639542377. The reversal of 639542357 is 753245936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 639533521 + 8836 = 25289^2 + 94^2 .

It is a cyclic number.

It is not a de Polignac number, because 639542357 - 2¹⁴ = 639525973 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639542327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319771178 + 319771179.

It is an arithmetic number, because the mean of its divisors is an integer number (319771179).

Almost surely, 2^639542357 is an apocalyptic number.

It is an amenable number.

639542357 is a deficient number, since it is larger than the sum of its proper divisors (1).

639542357 is an equidigital number, since it uses as much as digits as its factorization.

639542357 is an evil number, because the sum of its binary digits is even.

The product of its digits is 680400, while the sum is 44.

The square root of 639542357 is about 25289.1746998592. The cubic root of 639542357 is about 861.5684182924.

The spelling of 639542357 in words is "six hundred thirty-nine million, five hundred forty-two thousand, three hundred fifty-seven".