18156919 has 4 divisors (see below), whose sum is σ = 19807560. Its totient is φ = 16506280.

The previous prime is 18156911. The next prime is 18156923. The reversal of 18156919 is 91965181.

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 18156919 - 2³ = 18156911 is a prime.

It is a super-2 number, since 2×18156919² = 659347415145122, 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 (18156911) 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 3 ways as a sum of consecutive naturals, for example, 825304 + ... + 825325.

It is an arithmetic number, because the mean of its divisors is an integer number (4951890).

Almost surely, 2^18156919 is an apocalyptic number.

18156919 is a deficient number, since it is larger than the sum of its proper divisors (1650641).

18156919 is a wasteful number, since it uses less digits than its factorization.

18156919 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1650640.

The product of its digits is 19440, while the sum is 40.

The square root of 18156919 is about 4261.0936389617. The cubic root of 18156919 is about 262.8335002280.

The spelling of 18156919 in words is "eighteen million, one hundred fifty-six thousand, nine hundred nineteen".