638864745140 has 12 divisors (see below), whose sum is σ = 1341615964836. Its totient is φ = 255545898048.

The previous prime is 638864745137. The next prime is 638864745151. The reversal of 638864745140 is 41547468836.

It can be written as a sum of positive squares in 2 ways, for example, as 320269973776 + 318594771364 = 565924^2 + 564442^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15971618609 + ... + 15971618648.

It is an arithmetic number, because the mean of its divisors is an integer number (111801330403).

Almost surely, 2^638864745140 is an apocalyptic number.

It is an amenable number.

638864745140 is an abundant number, since it is smaller than the sum of its proper divisors (702751219696).

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

638864745140 is a wasteful number, since it uses less digits than its factorization.

638864745140 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31943237266 (or 31943237264 counting only the distinct ones).

The product of its (nonzero) digits is 15482880, while the sum is 56.

The spelling of 638864745140 in words is "six hundred thirty-eight billion, eight hundred sixty-four million, seven hundred forty-five thousand, one hundred forty".