638919447500 has 30 divisors (see below), whose sum is σ = 1397189053260. Its totient is φ = 255567778000.

The previous prime is 638919447493. The next prime is 638919447503. The reversal of 638919447500 is 5744919836.

It is not an unprimeable number, because it can be changed into a prime (638919447503) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 127781390 + ... + 127786389.

It is an arithmetic number, because the mean of its divisors is an integer number (46572968442).

Almost surely, 2^638919447500 is an apocalyptic number.

It is an amenable number.

638919447500 is an abundant number, since it is smaller than the sum of its proper divisors (758269605760).

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

638919447500 is a wasteful number, since it uses less digits than its factorization.

638919447500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 255567803 (or 255567786 counting only the distinct ones).

The product of its (nonzero) digits is 6531840, while the sum is 56.

The spelling of 638919447500 in words is "six hundred thirty-eight billion, nine hundred nineteen million, four hundred forty-seven thousand, five hundred".