165958321 has 2 divisors, whose sum is σ = 165958322. Its totient is φ = 165958320.

The previous prime is 165958297. The next prime is 165958333. The reversal of 165958321 is 123859561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 157778721 + 8179600 = 12561^2 + 2860^2 .

It is a cyclic number.

It is not a de Polignac number, because 165958321 - 2⁹ = 165957809 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165958021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82979160 + 82979161.

It is an arithmetic number, because the mean of its divisors is an integer number (82979161).

Almost surely, 2^165958321 is an apocalyptic number.

It is an amenable number.

165958321 is a deficient number, since it is larger than the sum of its proper divisors (1).

165958321 is an equidigital number, since it uses as much as digits as its factorization.

165958321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 64800, while the sum is 40.

The square root of 165958321 is about 12882.4811662971. The cubic root of 165958321 is about 549.5404657451.

The spelling of 165958321 in words is "one hundred sixty-five million, nine hundred fifty-eight thousand, three hundred twenty-one".