638655479 has 16 divisors (see below), whose sum is σ = 814767360. Its totient is φ = 486077760.

The previous prime is 638655463. The next prime is 638655481. The reversal of 638655479 is 974556836.

It is not a de Polignac number, because 638655479 - 2⁴ = 638655463 is a prime.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 638655479.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638655499) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 93134 + ... + 99755.

It is an arithmetic number, because the mean of its divisors is an integer number (50922960).

Almost surely, 2^638655479 is an apocalyptic number.

638655479 is a deficient number, since it is larger than the sum of its proper divisors (176111881).

638655479 is a wasteful number, since it uses less digits than its factorization.

638655479 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 192950.

The product of its digits is 5443200, while the sum is 53.

The square root of 638655479 is about 25271.6338806971. The cubic root of 638655479 is about 861.1699773631.

The spelling of 638655479 in words is "six hundred thirty-eight million, six hundred fifty-five thousand, four hundred seventy-nine".