18493421 has 2 divisors, whose sum is σ = 18493422. Its totient is φ = 18493420.

The previous prime is 18493393. The next prime is 18493457. The reversal of 18493421 is 12439481.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 9523396 + 8970025 = 3086^2 + 2995^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18493421 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18493471) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9246710 + 9246711.

It is an arithmetic number, because the mean of its divisors is an integer number (9246711).

Almost surely, 2^18493421 is an apocalyptic number.

It is an amenable number.

18493421 is a deficient number, since it is larger than the sum of its proper divisors (1).

18493421 is an equidigital number, since it uses as much as digits as its factorization.

18493421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6912, while the sum is 32.

The square root of 18493421 is about 4300.3977722997. The cubic root of 18493421 is about 264.4472684786.

The spelling of 18493421 in words is "eighteen million, four hundred ninety-three thousand, four hundred twenty-one".