18431997 has 4 divisors (see below), whose sum is σ = 24576000. Its totient is φ = 12287996.

The previous prime is 18431983. The next prime is 18431999. The reversal of 18431997 is 79913481.

It is a happy number.

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.

It is a cyclic number.

It is not a de Polignac number, because 18431997 - 2⁸ = 18431741 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18431999) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3071997 + ... + 3072002.

It is an arithmetic number, because the mean of its divisors is an integer number (6144000).

Almost surely, 2^18431997 is an apocalyptic number.

It is an amenable number.

18431997 is a deficient number, since it is larger than the sum of its proper divisors (6144003).

18431997 is an equidigital number, since it uses as much as digits as its factorization.

18431997 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6144002.

The product of its digits is 54432, while the sum is 42.

The square root of 18431997 is about 4293.2501674140. The cubic root of 18431997 is about 264.1541655803.

The spelling of 18431997 in words is "eighteen million, four hundred thirty-one thousand, nine hundred ninety-seven".