18421823 has 4 divisors (see below), whose sum is σ = 21053520. Its totient is φ = 15790128.

The previous prime is 18421813. The next prime is 18421841. The reversal of 18421823 is 32812481.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 18421823 - 2⁸ = 18421567 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 (18421813) 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, 1315838 + ... + 1315851.

It is an arithmetic number, because the mean of its divisors is an integer number (5263380).

Almost surely, 2^18421823 is an apocalyptic number.

18421823 is a deficient number, since it is larger than the sum of its proper divisors (2631697).

18421823 is an equidigital number, since it uses as much as digits as its factorization.

18421823 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2631696.

The product of its digits is 3072, while the sum is 29.

The square root of 18421823 is about 4292.0651206616. The cubic root of 18421823 is about 264.1055544773.

The spelling of 18421823 in words is "eighteen million, four hundred twenty-one thousand, eight hundred twenty-three".