165957691027 has 4 divisors (see below), whose sum is σ = 165960534376. Its totient is φ = 165954847680.

The previous prime is 165957690991. The next prime is 165957691033. The reversal of 165957691027 is 720196759561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165957691027 is a prime.

It is a super-2 number, since 2×165957691027² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165957691927) 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, 1332249 + ... + 1451482.

It is an arithmetic number, because the mean of its divisors is an integer number (41490133594).

Almost surely, 2^165957691027 is an apocalyptic number.

165957691027 is a deficient number, since it is larger than the sum of its proper divisors (2843349).

165957691027 is an equidigital number, since it uses as much as digits as its factorization.

165957691027 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2843348.

The product of its (nonzero) digits is 7144200, while the sum is 58.

The spelling of 165957691027 in words is "one hundred sixty-five billion, nine hundred fifty-seven million, six hundred ninety-one thousand, twenty-seven".