165251993 has 2 divisors, whose sum is σ = 165251994. Its totient is φ = 165251992.

The previous prime is 165251981. The next prime is 165252001. The reversal of 165251993 is 399152561.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 149035264 + 16216729 = 12208^2 + 4027^2 .

It is a cyclic number.

It is not a de Polignac number, because 165251993 - 2⁶ = 165251929 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165251993.

It is not a weakly prime, because it can be changed into another prime (165251923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82625996 + 82625997.

It is an arithmetic number, because the mean of its divisors is an integer number (82625997).

Almost surely, 2^165251993 is an apocalyptic number.

It is an amenable number.

165251993 is a deficient number, since it is larger than the sum of its proper divisors (1).

165251993 is an equidigital number, since it uses as much as digits as its factorization.

165251993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 72900, while the sum is 41.

The square root of 165251993 is about 12855.0376506644. The cubic root of 165251993 is about 548.7597319791.

The spelling of 165251993 in words is "one hundred sixty-five million, two hundred fifty-one thousand, nine hundred ninety-three".