638919690885 has 192 divisors, whose sum is σ = 1392171356160. Its totient is φ = 276659349120.

The previous prime is 638919690811. The next prime is 638919690901. The reversal of 638919690885 is 588096919836.

It is not a de Polignac number, because 638919690885 - 2¹⁰ = 638919689861 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 15650550 + ... + 15691320.

It is an arithmetic number, because the mean of its divisors is an integer number (7250892480).

Almost surely, 2^638919690885 is an apocalyptic number.

It is an amenable number.

638919690885 is an abundant number, since it is smaller than the sum of its proper divisors (753251665275).

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

638919690885 is a wasteful number, since it uses less digits than its factorization.

638919690885 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40925 (or 40912 counting only the distinct ones).

The product of its (nonzero) digits is 201553920, while the sum is 72.

The spelling of 638919690885 in words is "six hundred thirty-eight billion, nine hundred nineteen million, six hundred ninety thousand, eight hundred eighty-five".