638840727144 has 32 divisors (see below), whose sum is σ = 1774557576000. Its totient is φ = 212946908976.

The previous prime is 638840727143. The next prime is 638840727179. The reversal of 638840727144 is 441727048836.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (638840727143) 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, 1478797764 + ... + 1478798195.

It is an arithmetic number, because the mean of its divisors is an integer number (55454924250).

Almost surely, 2^638840727144 is an apocalyptic number.

It is an amenable number.

638840727144 is an abundant number, since it is smaller than the sum of its proper divisors (1135716848856).

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

638840727144 is a wasteful number, since it uses less digits than its factorization.

638840727144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2957595974 (or 2957595964 counting only the distinct ones).

The product of its (nonzero) digits is 7225344, while the sum is 54.

The spelling of 638840727144 in words is "six hundred thirty-eight billion, eight hundred forty million, seven hundred twenty-seven thousand, one hundred forty-four".