18919931 has 8 divisors (see below), whose sum is σ = 19148640. Its totient is φ = 18692928.

The previous prime is 18919907. The next prime is 18919939. The reversal of 18919931 is 13991981.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18919931 - 2¹⁸ = 18657787 is a prime.

It is a super-2 number, since 2×18919931² = 715927578089522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18919939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 46055 + ... + 46463.

It is an arithmetic number, because the mean of its divisors is an integer number (2393580).

Almost surely, 2^18919931 is an apocalyptic number.

18919931 is a deficient number, since it is larger than the sum of its proper divisors (228709).

18919931 is a wasteful number, since it uses less digits than its factorization.

18919931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 853.

The product of its digits is 17496, while the sum is 41.

The square root of 18919931 is about 4349.7047026206. The cubic root of 18919931 is about 266.4648015681.

The spelling of 18919931 in words is "eighteen million, nine hundred nineteen thousand, nine hundred thirty-one".