19717189121 has 4 divisors (see below), whose sum is σ = 22533930432. Its totient is φ = 16900447812.

The previous prime is 19717189073. The next prime is 19717189123. The reversal of 19717189121 is 12198171791.

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 19717189121 - 2³⁴ = 2537319937 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19717189123) 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, 1408370645 + ... + 1408370658.

It is an arithmetic number, because the mean of its divisors is an integer number (5633482608).

Almost surely, 2^19717189121 is an apocalyptic number.

It is an amenable number.

19717189121 is a deficient number, since it is larger than the sum of its proper divisors (2816741311).

19717189121 is an equidigital number, since it uses as much as digits as its factorization.

19717189121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2816741310.

The product of its digits is 63504, while the sum is 47.

The spelling of 19717189121 in words is "nineteen billion, seven hundred seventeen million, one hundred eighty-nine thousand, one hundred twenty-one".