17947997 has 4 divisors (see below), whose sum is σ = 18433116. Its totient is φ = 17462880.

The previous prime is 17947987. The next prime is 17948053. The reversal of 17947997 is 79974971.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 79974971 = 19 ⋅4209209.

It can be written as a sum of positive squares in 2 ways, for example, as 11363641 + 6584356 = 3371^2 + 2566^2 .

It is a cyclic number.

It is not a de Polignac number, because 17947997 - 2⁶ = 17947933 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 (17947907) 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, 242504 + ... + 242577.

It is an arithmetic number, because the mean of its divisors is an integer number (4608279).

Almost surely, 2^17947997 is an apocalyptic number.

It is an amenable number.

17947997 is a deficient number, since it is larger than the sum of its proper divisors (485119).

17947997 is an equidigital number, since it uses as much as digits as its factorization.

17947997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 485118.

The product of its digits is 1000188, while the sum is 53.

The square root of 17947997 is about 4236.5076419145. The cubic root of 17947997 is about 261.8215137318.

The spelling of 17947997 in words is "seventeen million, nine hundred forty-seven thousand, nine hundred ninety-seven".