4991638931 has 4 divisors (see below), whose sum is σ = 5113386264. Its totient is φ = 4869891600.

The previous prime is 4991638921. The next prime is 4991638969. The reversal of 4991638931 is 1398361994.

It is a happy number.

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 4991638931 - 2¹⁰ = 4991637907 is a prime.

It is a super-2 number, since 2×4991638931² = 49832918434949645522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (4991638921) 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, 60873605 + ... + 60873686.

It is an arithmetic number, because the mean of its divisors is an integer number (1278346566).

Almost surely, 2^4991638931 is an apocalyptic number.

4991638931 is a gapful number since it is divisible by the number (41) formed by its first and last digit.

4991638931 is a deficient number, since it is larger than the sum of its proper divisors (121747333).

4991638931 is a wasteful number, since it uses less digits than its factorization.

4991638931 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121747332.

The product of its digits is 1259712, while the sum is 53.

The square root of 4991638931 is about 70651.5316960645. The cubic root of 4991638931 is about 1709.0222664347.

The spelling of 4991638931 in words is "four billion, nine hundred ninety-one million, six hundred thirty-eight thousand, nine hundred thirty-one".