18343921 has 8 divisors (see below), whose sum is σ = 19042920. Its totient is φ = 17649408.

The previous prime is 18343891. The next prime is 18343931. The reversal of 18343921 is 12934381.

It can be written as a sum of positive squares in 4 ways, for example, as 2143296 + 16200625 = 1464^2 + 4025^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 18343921 - 2²³ = 9955313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18343931) 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, 8835 + ... + 10711.

It is an arithmetic number, because the mean of its divisors is an integer number (2380365).

Almost surely, 2^18343921 is an apocalyptic number.

It is an amenable number.

18343921 is a deficient number, since it is larger than the sum of its proper divisors (698999).

18343921 is a wasteful number, since it uses less digits than its factorization.

18343921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2243.

The product of its digits is 5184, while the sum is 31.

The square root of 18343921 is about 4282.9803875339. The cubic root of 18343921 is about 263.7327462640.

The spelling of 18343921 in words is "eighteen million, three hundred forty-three thousand, nine hundred twenty-one".