165139987 has 2 divisors, whose sum is σ = 165139988. Its totient is φ = 165139986.

The previous prime is 165139981. The next prime is 165140011. The reversal of 165139987 is 789931561.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 165139987 - 2¹¹ = 165137939 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 165139987.

It is not a weakly prime, because it can be changed into another prime (165139981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82569993 + 82569994.

It is an arithmetic number, because the mean of its divisors is an integer number (82569994).

Almost surely, 2^165139987 is an apocalyptic number.

165139987 is a deficient number, since it is larger than the sum of its proper divisors (1).

165139987 is an equidigital number, since it uses as much as digits as its factorization.

165139987 is an evil number, because the sum of its binary digits is even.

The product of its digits is 408240, while the sum is 49.

The square root of 165139987 is about 12850.6804100016. The cubic root of 165139987 is about 548.6357228354.

The spelling of 165139987 in words is "one hundred sixty-five million, one hundred thirty-nine thousand, nine hundred eighty-seven".