165158821 has 2 divisors, whose sum is σ = 165158822. Its totient is φ = 165158820.

The previous prime is 165158809. The next prime is 165158831. The reversal of 165158821 is 128851561.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 163481796 + 1677025 = 12786^2 + 1295^2 .

It is a cyclic number.

It is not a de Polignac number, because 165158821 - 2⁵ = 165158789 is a prime.

It is a super-2 number, since 2×165158821² = 54554872308220082, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165158831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82579410 + 82579411.

It is an arithmetic number, because the mean of its divisors is an integer number (82579411).

Almost surely, 2^165158821 is an apocalyptic number.

It is an amenable number.

165158821 is a deficient number, since it is larger than the sum of its proper divisors (1).

165158821 is an equidigital number, since it uses as much as digits as its factorization.

165158821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 19200, while the sum is 37.

The square root of 165158821 is about 12851.4131907740. The cubic root of 165158821 is about 548.6565791053.

The spelling of 165158821 in words is "one hundred sixty-five million, one hundred fifty-eight thousand, eight hundred twenty-one".