18423257 has 4 divisors (see below), whose sum is σ = 19506996. Its totient is φ = 17339520.

The previous prime is 18423241. The next prime is 18423259. The reversal of 18423257 is 75232481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 75232481 = 251 ⋅299731.

It can be written as a sum of positive squares in 2 ways, for example, as 8620096 + 9803161 = 2936^2 + 3131^2 .

It is a cyclic number.

It is not a de Polignac number, because 18423257 - 2⁴ = 18423241 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18423259) 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, 541844 + ... + 541877.

It is an arithmetic number, because the mean of its divisors is an integer number (4876749).

Almost surely, 2^18423257 is an apocalyptic number.

18423257 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

18423257 is a deficient number, since it is larger than the sum of its proper divisors (1083739).

18423257 is a wasteful number, since it uses less digits than its factorization.

18423257 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1083738.

The product of its digits is 13440, while the sum is 32.

The square root of 18423257 is about 4292.2321698622. The cubic root of 18423257 is about 264.1124071748.

The spelling of 18423257 in words is "eighteen million, four hundred twenty-three thousand, two hundred fifty-seven".