638187464 has 8 divisors (see below), whose sum is σ = 1196601510. Its totient is φ = 319093728.

The previous prime is 638187461. The next prime is 638187481. The reversal of 638187464 is 464781836.

It is a happy number.

638187464 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 637966564 + 220900 = 25258^2 + 470^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (638187461) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39886709 + ... + 39886724.

Almost surely, 2^638187464 is an apocalyptic number.

It is an amenable number.

638187464 is a deficient number, since it is larger than the sum of its proper divisors (558414046).

638187464 is a wasteful number, since it uses less digits than its factorization.

638187464 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79773439 (or 79773435 counting only the distinct ones).

The product of its digits is 774144, while the sum is 47.

The square root of 638187464 is about 25262.3724934932. The cubic root of 638187464 is about 860.9595671229.

The spelling of 638187464 in words is "six hundred thirty-eight million, one hundred eighty-seven thousand, four hundred sixty-four".