18921413 has 8 divisors (see below), whose sum is σ = 21695232. Its totient is φ = 16165296.

The previous prime is 18921379. The next prime is 18921431. The reversal of 18921413 is 31412981.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-18921413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18921443) 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, 2045 + ... + 6482.

It is an arithmetic number, because the mean of its divisors is an integer number (2711904).

Almost surely, 2^18921413 is an apocalyptic number.

It is an amenable number.

18921413 is a deficient number, since it is larger than the sum of its proper divisors (2773819).

18921413 is an equidigital number, since it uses as much as digits as its factorization.

18921413 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8851.

The product of its digits is 1728, while the sum is 29.

The square root of 18921413 is about 4349.8750556769. The cubic root of 18921413 is about 266.4717587909.

The spelling of 18921413 in words is "eighteen million, nine hundred twenty-one thousand, four hundred thirteen".