18813919 has 4 divisors (see below), whose sum is σ = 19251496. Its totient is φ = 18376344.

The previous prime is 18813913. The next prime is 18813941. The reversal of 18813919 is 91931881.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 18813919 - 2¹⁵ = 18781151 is a prime.

It is a super-2 number, since 2×18813919² = 707927096277122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18813913) 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, 218724 + ... + 218809.

It is an arithmetic number, because the mean of its divisors is an integer number (4812874).

Almost surely, 2^18813919 is an apocalyptic number.

18813919 is a deficient number, since it is larger than the sum of its proper divisors (437577).

18813919 is an equidigital number, since it uses as much as digits as its factorization.

18813919 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 437576.

The product of its digits is 15552, while the sum is 40.

The square root of 18813919 is about 4337.5014697404. The cubic root of 18813919 is about 265.9661846701.

The spelling of 18813919 in words is "eighteen million, eight hundred thirteen thousand, nine hundred nineteen".