638466664836 has 96 divisors (see below), whose sum is σ = 2000231267328. Its totient is φ = 153078917760.

The previous prime is 638466664831. The next prime is 638466664837.

638466664836 is nontrivially palindromic in base 10.

It is a Harshad number since it is a multiple of its sum of digits (66).

It is not an unprimeable number, because it can be changed into a prime (638466664831) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 26564190 + ... + 26588213.

It is an arithmetic number, because the mean of its divisors is an integer number (20835742368).

Almost surely, 2^638466664836 is an apocalyptic number.

638466664836 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

638466664836 is an abundant number, since it is smaller than the sum of its proper divisors (1361764602492).

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

638466664836 is a wasteful number, since it uses less digits than its factorization.

638466664836 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53152441 (or 53152439 counting only the distinct ones).

The product of its digits is 429981696, while the sum is 66.

The spelling of 638466664836 in words is "six hundred thirty-eight billion, four hundred sixty-six million, six hundred sixty-four thousand, eight hundred thirty-six".