638509891319 has 4 divisors (see below), whose sum is σ = 641536004760. Its totient is φ = 635483777880.

The previous prime is 638509891309. The next prime is 638509891337. The reversal of 638509891319 is 913198905836.

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-638509891319 is a prime.

It is a super-2 number, since 2×638509891319² (a number of 24 digits) 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 (638509891309) 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, 1513056404 + ... + 1513056825.

It is an arithmetic number, because the mean of its divisors is an integer number (160384001190).

Almost surely, 2^638509891319 is an apocalyptic number.

638509891319 is a deficient number, since it is larger than the sum of its proper divisors (3026113441).

638509891319 is a wasteful number, since it uses less digits than its factorization.

638509891319 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3026113440.

The product of its (nonzero) digits is 12597120, while the sum is 62.

The spelling of 638509891319 in words is "six hundred thirty-eight billion, five hundred nine million, eight hundred ninety-one thousand, three hundred nineteen".