638407402755 has 32 divisors (see below), whose sum is σ = 1046000355840. Its totient is φ = 332313139200.

The previous prime is 638407402753. The next prime is 638407402771. The reversal of 638407402755 is 557204704836.

It is a happy number.

It is not a de Polignac number, because 638407402755 - 2¹ = 638407402753 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 638407402698 and 638407402707.

It is not an unprimeable number, because it can be changed into a prime (638407402753) 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, 475555 + ... + 1225955.

It is an arithmetic number, because the mean of its divisors is an integer number (32687511120).

Almost surely, 2^638407402755 is an apocalyptic number.

638407402755 is a deficient number, since it is larger than the sum of its proper divisors (407592953085).

638407402755 is a wasteful number, since it uses less digits than its factorization.

638407402755 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 751771.

The product of its (nonzero) digits is 5644800, while the sum is 51.

The spelling of 638407402755 in words is "six hundred thirty-eight billion, four hundred seven million, four hundred two thousand, seven hundred fifty-five".