165656399 has 2 divisors, whose sum is σ = 165656400. Its totient is φ = 165656398.

The previous prime is 165656389. The next prime is 165656423. The reversal of 165656399 is 993656561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 165656399 - 2¹² = 165652303 is a prime.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (165656369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82828199 + 82828200.

It is an arithmetic number, because the mean of its divisors is an integer number (82828200).

Almost surely, 2^165656399 is an apocalyptic number.

165656399 is a deficient number, since it is larger than the sum of its proper divisors (1).

165656399 is an equidigital number, since it uses as much as digits as its factorization.

165656399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1312200, while the sum is 50.

The square root of 165656399 is about 12870.7575146143. The cubic root of 165656399 is about 549.2070103857.

The spelling of 165656399 in words is "one hundred sixty-five million, six hundred fifty-six thousand, three hundred ninety-nine".