19116997921 has 16 divisors (see below), whose sum is σ = 22449715200. Its totient is φ = 15937902288.

The previous prime is 19116997873. The next prime is 19116997927. The reversal of 19116997921 is 12979961191.

It is not a de Polignac number, because 19116997921 - 2⁹ = 19116997409 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19116997927) 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, 60931 + ... + 204808.

It is an arithmetic number, because the mean of its divisors is an integer number (1403107200).

Almost surely, 2^19116997921 is an apocalyptic number.

It is an amenable number.

19116997921 is a deficient number, since it is larger than the sum of its proper divisors (3332717279).

19116997921 is a wasteful number, since it uses less digits than its factorization.

19116997921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 266028.

The product of its digits is 551124, while the sum is 55.

The spelling of 19116997921 in words is "nineteen billion, one hundred sixteen million, nine hundred ninety-seven thousand, nine hundred twenty-one".