18457997 has 4 divisors (see below), whose sum is σ = 18530076. Its totient is φ = 18385920.

The previous prime is 18457991. The next prime is 18458023. The reversal of 18457997 is 79975481.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79975481 = 1481 ⋅54001.

It can be written as a sum of positive squares in 2 ways, for example, as 8128201 + 10329796 = 2851^2 + 3214^2 .

It is a cyclic number.

It is not a de Polignac number, because 18457997 - 2¹⁰ = 18456973 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 (18457991) 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, 35654 + ... + 36167.

It is an arithmetic number, because the mean of its divisors is an integer number (4632519).

Almost surely, 2^18457997 is an apocalyptic number.

It is an amenable number.

18457997 is a deficient number, since it is larger than the sum of its proper divisors (72079).

18457997 is an equidigital number, since it uses as much as digits as its factorization.

18457997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72078.

The product of its digits is 635040, while the sum is 50.

The square root of 18457997 is about 4296.2771093122. The cubic root of 18457997 is about 264.2783116783.

The spelling of 18457997 in words is "eighteen million, four hundred fifty-seven thousand, nine hundred ninety-seven".