639054557 has 2 divisors, whose sum is σ = 639054558. Its totient is φ = 639054556.

The previous prime is 639054511. The next prime is 639054571. The reversal of 639054557 is 755450936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 635745796 + 3308761 = 25214^2 + 1819^2 .

It is a cyclic number.

It is not a de Polignac number, because 639054557 - 2¹⁴ = 639038173 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (639054587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319527278 + 319527279.

It is an arithmetic number, because the mean of its divisors is an integer number (319527279).

Almost surely, 2^639054557 is an apocalyptic number.

It is an amenable number.

639054557 is a deficient number, since it is larger than the sum of its proper divisors (1).

639054557 is an equidigital number, since it uses as much as digits as its factorization.

639054557 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 567000, while the sum is 44.

The square root of 639054557 is about 25279.5284172787. The cubic root of 639054557 is about 861.3493137159.

The spelling of 639054557 in words is "six hundred thirty-nine million, fifty-four thousand, five hundred fifty-seven".