18914899921 has 4 divisors (see below), whose sum is σ = 18921890032. Its totient is φ = 18907909812.

The previous prime is 18914899903. The next prime is 18914899957. The reversal of 18914899921 is 12999841981.

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 18914899921 - 2⁷ = 18914899793 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18914899921.

It is not an unprimeable number, because it can be changed into a prime (18914819921) 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, 3490995 + ... + 3496408.

It is an arithmetic number, because the mean of its divisors is an integer number (4730472508).

Almost surely, 2^18914899921 is an apocalyptic number.

It is an amenable number.

18914899921 is a deficient number, since it is larger than the sum of its proper divisors (6990111).

18914899921 is an equidigital number, since it uses as much as digits as its factorization.

18914899921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6990110.

The product of its digits is 3359232, while the sum is 61.

The spelling of 18914899921 in words is "eighteen billion, nine hundred fourteen million, eight hundred ninety-nine thousand, nine hundred twenty-one".