165997031 has 4 divisors (see below), whose sum is σ = 168810600. Its totient is φ = 163183464.

The previous prime is 165997021. The next prime is 165997067. The reversal of 165997031 is 130799561.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 130799561 = 353 ⋅370537.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-165997031 is a prime.

It is a super-2 number, since 2×165997031² = 55110028601629922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 165997031.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165997021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1406696 + ... + 1406813.

It is an arithmetic number, because the mean of its divisors is an integer number (42202650).

Almost surely, 2^165997031 is an apocalyptic number.

165997031 is a deficient number, since it is larger than the sum of its proper divisors (2813569).

165997031 is an equidigital number, since it uses as much as digits as its factorization.

165997031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2813568.

The product of its (nonzero) digits is 51030, while the sum is 41.

The square root of 165997031 is about 12883.9835066644. The cubic root of 165997031 is about 549.5831894393.

The spelling of 165997031 in words is "one hundred sixty-five million, nine hundred ninety-seven thousand, thirty-one".