165917987 has 8 divisors (see below), whose sum is σ = 168953472. Its totient is φ = 162892800.

The previous prime is 165917957. The next prime is 165918031. The reversal of 165917987 is 789719561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 165917987 - 2⁶ = 165917923 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165917957) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 34787 + ... + 39267.

It is an arithmetic number, because the mean of its divisors is an integer number (21119184).

Almost surely, 2^165917987 is an apocalyptic number.

165917987 is a deficient number, since it is larger than the sum of its proper divisors (3035485).

165917987 is an equidigital number, since it uses as much as digits as its factorization.

165917987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5149.

The product of its digits is 952560, while the sum is 53.

The square root of 165917987 is about 12880.9156118655. The cubic root of 165917987 is about 549.4959425964.

The spelling of 165917987 in words is "one hundred sixty-five million, nine hundred seventeen thousand, nine hundred eighty-seven".