18611321 has 4 divisors (see below), whose sum is σ = 18962532. Its totient is φ = 18260112.

The previous prime is 18611297. The next prime is 18611363. The reversal of 18611321 is 12311681.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12311681 = 31 ⋅397151.

It can be written as a sum of positive squares in 2 ways, for example, as 9369721 + 9241600 = 3061^2 + 3040^2 .

It is a cyclic number.

It is not a de Polignac number, because 18611321 - 2¹⁴ = 18594937 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18611381) 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, 175526 + ... + 175631.

It is an arithmetic number, because the mean of its divisors is an integer number (4740633).

Almost surely, 2^18611321 is an apocalyptic number.

It is an amenable number.

18611321 is a deficient number, since it is larger than the sum of its proper divisors (351211).

18611321 is an equidigital number, since it uses as much as digits as its factorization.

18611321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 351210.

The product of its digits is 288, while the sum is 23.

The square root of 18611321 is about 4314.0840279253. The cubic root of 18611321 is about 265.0080500699.

The spelling of 18611321 in words is "eighteen million, six hundred eleven thousand, three hundred twenty-one".