18360421 has 4 divisors (see below), whose sum is σ = 18371500. Its totient is φ = 18349344.

The previous prime is 18360389. The next prime is 18360427. The reversal of 18360421 is 12406381.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 17181025 + 1179396 = 4145^2 + 1086^2 .

It is a cyclic number.

It is not a de Polignac number, because 18360421 - 2⁵ = 18360389 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 (18360427) 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, 2496 + ... + 6553.

It is an arithmetic number, because the mean of its divisors is an integer number (4592875).

Almost surely, 2^18360421 is an apocalyptic number.

It is an amenable number.

18360421 is a deficient number, since it is larger than the sum of its proper divisors (11079).

18360421 is an equidigital number, since it uses as much as digits as its factorization.

18360421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11078.

The product of its (nonzero) digits is 1152, while the sum is 25.

The square root of 18360421 is about 4284.9061833370. The cubic root of 18360421 is about 263.8117967251.

It can be divided in two parts, 18360 and 421, that added together give a palindrome (18781).

The spelling of 18360421 in words is "eighteen million, three hundred sixty thousand, four hundred twenty-one".