639974777 has 24 divisors (see below), whose sum is σ = 733376160. Its totient is φ = 556657920.

The previous prime is 639974771. The next prime is 639974789. The reversal of 639974777 is 777479936.

It is not a de Polignac number, because 639974777 - 2⁸ = 639974521 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (639974771) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 773438 + ... + 774264.

It is an arithmetic number, because the mean of its divisors is an integer number (30557340).

Almost surely, 2^639974777 is an apocalyptic number.

It is an amenable number.

639974777 is a deficient number, since it is larger than the sum of its proper divisors (93401383).

639974777 is a wasteful number, since it uses less digits than its factorization.

639974777 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1113 (or 1100 counting only the distinct ones).

The product of its digits is 14002632, while the sum is 59.

The square root of 639974777 is about 25297.7227631263. The cubic root of 639974777 is about 861.7625547586.

The spelling of 639974777 in words is "six hundred thirty-nine million, nine hundred seventy-four thousand, seven hundred seventy-seven".