165985975 has 6 divisors (see below), whose sum is σ = 205822640. Its totient is φ = 132788760.

The previous prime is 165985969. The next prime is 165985991. The reversal of 165985975 is 579589561.

It is not a de Polignac number, because 165985975 - 2⁷ = 165985847 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3319695 + ... + 3319744.

Almost surely, 2^165985975 is an apocalyptic number.

165985975 is a deficient number, since it is larger than the sum of its proper divisors (39836665).

165985975 is an equidigital number, since it uses as much as digits as its factorization.

165985975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6639449 (or 6639444 counting only the distinct ones).

The product of its digits is 3402000, while the sum is 55.

The square root of 165985975 is about 12883.5544396723. The cubic root of 165985975 is about 549.5709877620.

The spelling of 165985975 in words is "one hundred sixty-five million, nine hundred eighty-five thousand, nine hundred seventy-five".