638745943 has 4 divisors (see below), whose sum is σ = 696813768. Its totient is φ = 580678120.

The previous prime is 638745931. The next prime is 638745959. The reversal of 638745943 is 349547836.

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

It is not a de Polignac number, because 638745943 - 2⁹ = 638745431 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 (638745143) 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, 29033896 + ... + 29033917.

It is an arithmetic number, because the mean of its divisors is an integer number (174203442).

Almost surely, 2^638745943 is an apocalyptic number.

638745943 is a deficient number, since it is larger than the sum of its proper divisors (58067825).

638745943 is a wasteful number, since it uses less digits than its factorization.

638745943 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 58067824.

The product of its digits is 2177280, while the sum is 49.

The square root of 638745943 is about 25273.4236501508. The cubic root of 638745943 is about 861.2106363231.

The spelling of 638745943 in words is "six hundred thirty-eight million, seven hundred forty-five thousand, nine hundred forty-three".