638801660 has 48 divisors (see below), whose sum is σ = 1613821440. Its totient is φ = 207489600.

The previous prime is 638801627. The next prime is 638801677. The reversal of 638801660 is 66108836.

It is a Harshad number since it is a multiple of its sum of digits (38).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 117416 + ... + 122735.

It is an arithmetic number, because the mean of its divisors is an integer number (33621280).

Almost surely, 2^638801660 is an apocalyptic number.

It is an amenable number.

638801660 is an abundant number, since it is smaller than the sum of its proper divisors (975019780).

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

638801660 is a wasteful number, since it uses less digits than its factorization.

638801660 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 240186 (or 240184 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 38.

The square root of 638801660 is about 25274.5259104894. The cubic root of 638801660 is about 861.2356763662.

The spelling of 638801660 in words is "six hundred thirty-eight million, eight hundred one thousand, six hundred sixty".