639547387 has 2 divisors, whose sum is σ = 639547388. Its totient is φ = 639547386.

The previous prime is 639547351. The next prime is 639547417. The reversal of 639547387 is 783745936.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 639547387 - 2²⁷ = 505329659 is a prime.

It is not a weakly prime, because it can be changed into another prime (639544387) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 319773693 + 319773694.

It is an arithmetic number, because the mean of its divisors is an integer number (319773694).

Almost surely, 2^639547387 is an apocalyptic number.

639547387 is a deficient number, since it is larger than the sum of its proper divisors (1).

639547387 is an equidigital number, since it uses as much as digits as its factorization.

639547387 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3810240, while the sum is 52.

The square root of 639547387 is about 25289.2741493306. The cubic root of 639547387 is about 861.5706770313.

The spelling of 639547387 in words is "six hundred thirty-nine million, five hundred forty-seven thousand, three hundred eighty-seven".