638407724123 has 4 divisors (see below), whose sum is σ = 687516010608. Its totient is φ = 589299437640.

The previous prime is 638407724117. The next prime is 638407724147. The reversal of 638407724123 is 321427704836.

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

It is a cyclic number.

It is not a de Polignac number, because 638407724123 - 2⁴ = 638407724107 is a prime.

It is a super-2 number, since 2×638407724123² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (638407724153) 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, 24554143223 + ... + 24554143248.

It is an arithmetic number, because the mean of its divisors is an integer number (171879002652).

Almost surely, 2^638407724123 is an apocalyptic number.

638407724123 is a deficient number, since it is larger than the sum of its proper divisors (49108286485).

638407724123 is a wasteful number, since it uses less digits than its factorization.

638407724123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49108286484.

The product of its (nonzero) digits is 1354752, while the sum is 47.

The spelling of 638407724123 in words is "six hundred thirty-eight billion, four hundred seven million, seven hundred twenty-four thousand, one hundred twenty-three".