18719961 has 12 divisors (see below), whose sum is σ = 27028368. Its totient is φ = 11519664.

The previous prime is 18719957. The next prime is 18719963. The reversal of 18719961 is 16991781.

It is not a de Polignac number, because 18719961 - 2² = 18719957 is a prime.

It is not an unprimeable number, because it can be changed into a prime (18719963) 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 11 ways as a sum of consecutive naturals, for example, 17955 + ... + 18968.

It is an arithmetic number, because the mean of its divisors is an integer number (2252364).

Almost surely, 2^18719961 is an apocalyptic number.

It is an amenable number.

18719961 is a deficient number, since it is larger than the sum of its proper divisors (8308407).

18719961 is a wasteful number, since it uses less digits than its factorization.

18719961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36952 (or 36939 counting only the distinct ones).

The product of its digits is 27216, while the sum is 42.

The square root of 18719961 is about 4326.6570236153. The cubic root of 18719961 is about 265.5226944613.

The spelling of 18719961 in words is "eighteen million, seven hundred nineteen thousand, nine hundred sixty-one".