165731987 has 2 divisors, whose sum is σ = 165731988. Its totient is φ = 165731986.

The previous prime is 165731981. The next prime is 165732067. The reversal of 165731987 is 789137561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 165731987 - 2⁴ = 165731971 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (165731981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82865993 + 82865994.

It is an arithmetic number, because the mean of its divisors is an integer number (82865994).

Almost surely, 2^165731987 is an apocalyptic number.

165731987 is a deficient number, since it is larger than the sum of its proper divisors (1).

165731987 is an equidigital number, since it uses as much as digits as its factorization.

165731987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 317520, while the sum is 47.

The square root of 165731987 is about 12873.6936036244. The cubic root of 165731987 is about 549.2905309484.

The spelling of 165731987 in words is "one hundred sixty-five million, seven hundred thirty-one thousand, nine hundred eighty-seven".