18719999 has 8 divisors (see below), whose sum is σ = 19647360. Its totient is φ = 17802136.

The previous prime is 18719983. The next prime is 18720083. The reversal of 18719999 is 99991781.

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 18719999 - 2⁴ = 18719983 is a prime.

It is a Duffinian number.

18719999 is a modest number, since divided by 9999 gives 1871 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 18719999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18719929) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1844 + ... + 6390.

It is an arithmetic number, because the mean of its divisors is an integer number (2455920).

Almost surely, 2^18719999 is an apocalyptic number.

18719999 is a deficient number, since it is larger than the sum of its proper divisors (927361).

18719999 is a wasteful number, since it uses less digits than its factorization.

18719999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4749.

The product of its digits is 367416, while the sum is 53.

The square root of 18719999 is about 4326.6614149942. The cubic root of 18719999 is about 265.5228741244.

The spelling of 18719999 in words is "eighteen million, seven hundred nineteen thousand, nine hundred ninety-nine".