638615676426 has 64 divisors (see below), whose sum is σ = 1573257772800. Its totient is φ = 168288892416.

The previous prime is 638615676407. The next prime is 638615676431. The reversal of 638615676426 is 624676516836.

It is a self number, because there is not a number n which added to its sum of digits gives 638615676426.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 195190 + ... + 1146878.

It is an arithmetic number, because the mean of its divisors is an integer number (24582152700).

Almost surely, 2^638615676426 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638615676426, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (786628886400).

638615676426 is an abundant number, since it is smaller than the sum of its proper divisors (934642096374).

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

638615676426 is a wasteful number, since it uses less digits than its factorization.

638615676426 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 952943.

The product of its digits is 52254720, while the sum is 60.

The spelling of 638615676426 in words is "six hundred thirty-eight billion, six hundred fifteen million, six hundred seventy-six thousand, four hundred twenty-six".