638958743 has 4 divisors (see below), whose sum is σ = 639476520. Its totient is φ = 638440968.

The previous prime is 638958709. The next prime is 638958767. The reversal of 638958743 is 347859836.

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 638958743 - 2⁸ = 638958487 is a prime.

It is a super-2 number, since 2×638958743² = 816536550512280098, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (638958703) 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, 257033 + ... + 259506.

It is an arithmetic number, because the mean of its divisors is an integer number (159869130).

Almost surely, 2^638958743 is an apocalyptic number.

638958743 is a deficient number, since it is larger than the sum of its proper divisors (517777).

638958743 is a wasteful number, since it uses less digits than its factorization.

638958743 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517776.

The product of its digits is 4354560, while the sum is 53.

The square root of 638958743 is about 25277.6332555087. The cubic root of 638958743 is about 861.3062639496.

The spelling of 638958743 in words is "six hundred thirty-eight million, nine hundred fifty-eight thousand, seven hundred forty-three".