638444764 has 48 divisors (see below), whose sum is σ = 1233388800. Its totient is φ = 287819136.

The previous prime is 638444759. The next prime is 638444767. The reversal of 638444764 is 467444836.

638444764 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×638444764² = 815223433358031392, which contains 22 as substring.

It is a Smith number, since the sum of its digits (46) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (46).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638444767) 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, 395992 + ... + 397600.

It is an arithmetic number, because the mean of its divisors is an integer number (25695600).

Almost surely, 2^638444764 is an apocalyptic number.

It is an amenable number.

638444764 is a deficient number, since it is larger than the sum of its proper divisors (594944036).

638444764 is a wasteful number, since it uses less digits than its factorization.

638444764 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1882 (or 1880 counting only the distinct ones).

The product of its digits is 1548288, while the sum is 46.

The square root of 638444764 is about 25267.4645344562. The cubic root of 638444764 is about 861.0752568143.

The spelling of 638444764 in words is "six hundred thirty-eight million, four hundred forty-four thousand, seven hundred sixty-four".