165910681 has 2 divisors, whose sum is σ = 165910682. Its totient is φ = 165910680.

The previous prime is 165910631. The next prime is 165910721. The reversal of 165910681 is 186019561.

165910681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 104366656 + 61544025 = 10216^2 + 7845^2 .

It is a cyclic number.

It is not a de Polignac number, because 165910681 - 2¹³ = 165902489 is a prime.

It is a super-2 number, since 2×165910681² = 55052708139767522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 165910681.

It is not a weakly prime, because it can be changed into another prime (165910631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82955340 + 82955341.

It is an arithmetic number, because the mean of its divisors is an integer number (82955341).

Almost surely, 2^165910681 is an apocalyptic number.

It is an amenable number.

165910681 is a deficient number, since it is larger than the sum of its proper divisors (1).

165910681 is an equidigital number, since it uses as much as digits as its factorization.

165910681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12960, while the sum is 37.

The square root of 165910681 is about 12880.6320108914. The cubic root of 165910681 is about 549.4878770126.

The spelling of 165910681 in words is "one hundred sixty-five million, nine hundred ten thousand, six hundred eighty-one".