17985997 has 4 divisors (see below), whose sum is σ = 18404320. Its totient is φ = 17567676.

The previous prime is 17985991. The next prime is 17986013. The reversal of 17985997 is 79958971.

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: 79958971 = 23 ⋅3476477.

It is a cyclic number.

It is not a de Polignac number, because 17985997 - 2¹⁹ = 17461709 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 (17985991) 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, 209097 + ... + 209182.

It is an arithmetic number, because the mean of its divisors is an integer number (4601080).

Almost surely, 2^17985997 is an apocalyptic number.

It is an amenable number.

17985997 is a deficient number, since it is larger than the sum of its proper divisors (418323).

17985997 is an equidigital number, since it uses as much as digits as its factorization.

17985997 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 418322.

The product of its digits is 1428840, while the sum is 55.

The square root of 17985997 is about 4240.9900966637. The cubic root of 17985997 is about 262.0061620834.

The spelling of 17985997 in words is "seventeen million, nine hundred eighty-five thousand, nine hundred ninety-seven".