638305318 has 16 divisors (see below), whose sum is σ = 1094755104. Its totient is φ = 273430080.

The previous prime is 638305313. The next prime is 638305337. The reversal of 638305318 is 813503836.

It is a super-2 number, since 2×638305318² = 814867357974162248, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638305313) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 23688 + ... + 42868.

It is an arithmetic number, because the mean of its divisors is an integer number (68422194).

Almost surely, 2^638305318 is an apocalyptic number.

638305318 is a deficient number, since it is larger than the sum of its proper divisors (456449786).

638305318 is a wasteful number, since it uses less digits than its factorization.

638305318 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21567.

The product of its (nonzero) digits is 51840, while the sum is 37.

The square root of 638305318 is about 25264.7049854139. The cubic root of 638305318 is about 861.0125616264.

The spelling of 638305318 in words is "six hundred thirty-eight million, three hundred five thousand, three hundred eighteen".