638431707 has 32 divisors (see below), whose sum is σ = 900739840. Its totient is φ = 401708160.

The previous prime is 638431687. The next prime is 638431721. The reversal of 638431707 is 707134836.

It is not a de Polignac number, because 638431707 - 2⁷ = 638431579 is a prime.

It is not an unprimeable number, because it can be changed into a prime (638431757) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 863544 + ... + 864282.

It is an arithmetic number, because the mean of its divisors is an integer number (28148120).

Almost surely, 2^638431707 is an apocalyptic number.

638431707 is a deficient number, since it is larger than the sum of its proper divisors (262308133).

638431707 is a wasteful number, since it uses less digits than its factorization.

638431707 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1003.

The product of its (nonzero) digits is 84672, while the sum is 39.

The square root of 638431707 is about 25267.2061573891. The cubic root of 638431707 is about 861.0693867496.

The spelling of 638431707 in words is "six hundred thirty-eight million, four hundred thirty-one thousand, seven hundred seven".