7981918837 has 4 divisors (see below), whose sum is σ = 7982748160. Its totient is φ = 7981089516.

The previous prime is 7981918783. The next prime is 7981918883. The reversal of 7981918837 is 7388191897.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 7981918837 - 2⁷ = 7981918709 is a prime.

It is a super-2 number, since 2×7981918837² (a number of 21 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 (7981918337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 400053 + ... + 419530.

It is an arithmetic number, because the mean of its divisors is an integer number (1995687040).

Almost surely, 2^7981918837 is an apocalyptic number.

It is an amenable number.

7981918837 is a deficient number, since it is larger than the sum of its proper divisors (829323).

7981918837 is an equidigital number, since it uses as much as digits as its factorization.

7981918837 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 829322.

The product of its digits is 6096384, while the sum is 61.

The square root of 7981918837 is about 89341.5851493581. The cubic root of 7981918837 is about 1998.4920998209.

The spelling of 7981918837 in words is "seven billion, nine hundred eighty-one million, nine hundred eighteen thousand, eight hundred thirty-seven".