638475425279 has 4 divisors (see below), whose sum is σ = 638486991240. Its totient is φ = 638463859320.

The previous prime is 638475425267. The next prime is 638475425293. The reversal of 638475425279 is 972524574836.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-638475425279 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638475425239) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5699777 + ... + 5810714.

It is an arithmetic number, because the mean of its divisors is an integer number (159621747810).

Almost surely, 2^638475425279 is an apocalyptic number.

638475425279 is a deficient number, since it is larger than the sum of its proper divisors (11565961).

638475425279 is a wasteful number, since it uses less digits than its factorization.

638475425279 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11565960.

The product of its digits is 101606400, while the sum is 62.

The spelling of 638475425279 in words is "six hundred thirty-eight billion, four hundred seventy-five million, four hundred twenty-five thousand, two hundred seventy-nine".