638376212640 has 192 divisors, whose sum is σ = 2132929895040. Its totient is φ = 159937167360.

The previous prime is 638376212629. The next prime is 638376212659. The reversal of 638376212640 is 46212673836.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 638376212640.

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, 4574295 + ... + 4711785.

It is an arithmetic number, because the mean of its divisors is an integer number (11109009870).

Almost surely, 2^638376212640 is an apocalyptic number.

638376212640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 638376212640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1066464947520).

638376212640 is an abundant number, since it is smaller than the sum of its proper divisors (1494553682400).

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

638376212640 is a wasteful number, since it uses less digits than its factorization.

638376212640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138095 (or 138087 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 48.

The spelling of 638376212640 in words is "six hundred thirty-eight billion, three hundred seventy-six million, two hundred twelve thousand, six hundred forty".