18971971199 has 16 divisors (see below), whose sum is σ = 20029261824. Its totient is φ = 17934708000.

The previous prime is 18971971189. The next prime is 18971971211. The reversal of 18971971199 is 99117917981.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 18971971199 - 2¹² = 18971967103 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18971971159) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1319282 + ... + 1333584.

It is an arithmetic number, because the mean of its divisors is an integer number (1251828864).

Almost surely, 2^18971971199 is an apocalyptic number.

18971971199 is a deficient number, since it is larger than the sum of its proper divisors (1057290625).

18971971199 is a wasteful number, since it uses less digits than its factorization.

18971971199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14998.

The product of its digits is 2571912, while the sum is 62.

The spelling of 18971971199 in words is "eighteen billion, nine hundred seventy-one million, nine hundred seventy-one thousand, one hundred ninety-nine".