18641393 has 4 divisors (see below), whose sum is σ = 18877440. Its totient is φ = 18405348.

The previous prime is 18641387. The next prime is 18641419. The reversal of 18641393 is 39314681.

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, and also an emirpimes, since its reverse is a distinct semiprime: 39314681 = 7 ⋅5616383.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18641393 is a prime.

It is a super-3 number, since 3×18641393³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18641893) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 117905 + ... + 118062.

It is an arithmetic number, because the mean of its divisors is an integer number (4719360).

Almost surely, 2^18641393 is an apocalyptic number.

It is an amenable number.

18641393 is a deficient number, since it is larger than the sum of its proper divisors (236047).

18641393 is an equidigital number, since it uses as much as digits as its factorization.

18641393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236046.

The product of its digits is 15552, while the sum is 35.

The square root of 18641393 is about 4317.5679496680. The cubic root of 18641393 is about 265.1507057807.

The spelling of 18641393 in words is "eighteen million, six hundred forty-one thousand, three hundred ninety-three".