165243997 has 2 divisors, whose sum is σ = 165243998. Its totient is φ = 165243996.

The previous prime is 165243989. The next prime is 165244003. The reversal of 165243997 is 799342561.

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., 138556441 + 26687556 = 11771^2 + 5166^2 .

It is a cyclic number.

It is not a de Polignac number, because 165243997 - 2³ = 165243989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165243497) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82621998 + 82621999.

It is an arithmetic number, because the mean of its divisors is an integer number (82621999).

Almost surely, 2^165243997 is an apocalyptic number.

It is an amenable number.

165243997 is a deficient number, since it is larger than the sum of its proper divisors (1).

165243997 is an equidigital number, since it uses as much as digits as its factorization.

165243997 is an evil number, because the sum of its binary digits is even.

The product of its digits is 408240, while the sum is 46.

The square root of 165243997 is about 12854.7266404230. The cubic root of 165243997 is about 548.7508809439.

The spelling of 165243997 in words is "one hundred sixty-five million, two hundred forty-three thousand, nine hundred ninety-seven".