18423997 has 4 divisors (see below), whose sum is σ = 18438336. Its totient is φ = 18409660.

The previous prime is 18423967. The next prime is 18424027. The reversal of 18423997 is 79932481.

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: 79932481 = 997 ⋅80173.

It is an interprime number because it is at equal distance from previous prime (18423967) and next prime (18424027).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18423997 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 (18423907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5029 + ... + 7882.

It is an arithmetic number, because the mean of its divisors is an integer number (4609584).

Almost surely, 2^18423997 is an apocalyptic number.

It is an amenable number.

18423997 is a deficient number, since it is larger than the sum of its proper divisors (14339).

18423997 is a wasteful number, since it uses less digits than its factorization.

18423997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14338.

The product of its digits is 108864, while the sum is 43.

The square root of 18423997 is about 4292.3183712302. The cubic root of 18423997 is about 264.1159432952.

The spelling of 18423997 in words is "eighteen million, four hundred twenty-three thousand, nine hundred ninety-seven".