18990719 has 4 divisors (see below), whose sum is σ = 20717160. Its totient is φ = 17264280.

The previous prime is 18990707. The next prime is 18990721. The reversal of 18990719 is 91709981.

It is a semiprime because it is the product of two primes.

It is a de Polignac number, because none of the positive numbers 2^k-18990719 is a prime.

It is a super-2 number, since 2×18990719² = 721294816273922, which contains 22 as substring.

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 18990719.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18990779) 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, 863204 + ... + 863225.

It is an arithmetic number, because the mean of its divisors is an integer number (5179290).

Almost surely, 2^18990719 is an apocalyptic number.

18990719 is a deficient number, since it is larger than the sum of its proper divisors (1726441).

18990719 is a wasteful number, since it uses less digits than its factorization.

18990719 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1726440.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 18990719 is about 4357.8342097882. The cubic root of 18990719 is about 266.7967096630.

The spelling of 18990719 in words is "eighteen million, nine hundred ninety thousand, seven hundred nineteen".