18971971198 has 4 divisors (see below), whose sum is σ = 28457956800. Its totient is φ = 9485985598.

The previous prime is 18971971189. The next prime is 18971971211. The reversal of 18971971198 is 89117917981.

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

It is a super-2 number, since 2×18971971198² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4742992798 + ... + 4742992801.

It is an arithmetic number, because the mean of its divisors is an integer number (7114489200).

Almost surely, 2^18971971198 is an apocalyptic number.

18971971198 is a deficient number, since it is larger than the sum of its proper divisors (9485985602).

18971971198 is an equidigital number, since it uses as much as digits as its factorization.

18971971198 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9485985601.

The product of its digits is 2286144, while the sum is 61.

The spelling of 18971971198 in words is "eighteen billion, nine hundred seventy-one million, nine hundred seventy-one thousand, one hundred ninety-eight".