638405133423 has 4 divisors (see below), whose sum is σ = 851206844568. Its totient is φ = 425603422280.

The previous prime is 638405133407. The next prime is 638405133491. The reversal of 638405133423 is 324331504836.

638405133423 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 638405133423 - 2⁴ = 638405133407 is a prime.

It is a super-2 number, since 2×638405133423² (a number of 24 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638405173423) 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, 106400855568 + ... + 106400855573.

It is an arithmetic number, because the mean of its divisors is an integer number (212801711142).

Almost surely, 2^638405133423 is an apocalyptic number.

638405133423 is a deficient number, since it is larger than the sum of its proper divisors (212801711145).

638405133423 is a wasteful number, since it uses less digits than its factorization.

638405133423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 212801711144.

The product of its (nonzero) digits is 622080, while the sum is 42.

The spelling of 638405133423 in words is "six hundred thirty-eight billion, four hundred five million, one hundred thirty-three thousand, four hundred twenty-three".