638489740416 has 64 divisors (see below), whose sum is σ = 1850169146400. Its totient is φ = 193481738240.

The previous prime is 638489740411. The next prime is 638489740433. The reversal of 638489740416 is 614047984836.

It is a tau number, because it is divible by the number of its divisors (64).

It is a self number, because there is not a number n which added to its sum of digits gives 638489740416.

It is not an unprimeable number, because it can be changed into a prime (638489740411) 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, 75574581 + ... + 75583028.

Almost surely, 2^638489740416 is an apocalyptic number.

638489740416 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

638489740416 is an abundant number, since it is smaller than the sum of its proper divisors (1211679405984).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

638489740416 is a wasteful number, since it uses less digits than its factorization.

638489740416 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151157637 (or 151157625 counting only the distinct ones).

The product of its (nonzero) digits is 27869184, while the sum is 60.

The spelling of 638489740416 in words is "six hundred thirty-eight billion, four hundred eighty-nine million, seven hundred forty thousand, four hundred sixteen".