18851321 has 4 divisors (see below), whose sum is σ = 19132752. Its totient is φ = 18569892.

The previous prime is 18851311. The next prime is 18851333. The reversal of 18851321 is 12315881.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18851321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18851311) 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, 140615 + ... + 140748.

It is an arithmetic number, because the mean of its divisors is an integer number (4783188).

Almost surely, 2^18851321 is an apocalyptic number.

It is an amenable number.

18851321 is a deficient number, since it is larger than the sum of its proper divisors (281431).

18851321 is an equidigital number, since it uses as much as digits as its factorization.

18851321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281430.

The product of its digits is 1920, while the sum is 29.

The square root of 18851321 is about 4341.8107973517. The cubic root of 18851321 is about 266.1423145970.

The spelling of 18851321 in words is "eighteen million, eight hundred fifty-one thousand, three hundred twenty-one".