165994187 has 4 divisors (see below), whose sum is σ = 166040760. Its totient is φ = 165947616.

The previous prime is 165994163. The next prime is 165994193. The reversal of 165994187 is 781499561.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 165994187 - 2¹⁴ = 165977803 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165994487) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17453 + ... + 25230.

It is an arithmetic number, because the mean of its divisors is an integer number (41510190).

Almost surely, 2^165994187 is an apocalyptic number.

165994187 is a deficient number, since it is larger than the sum of its proper divisors (46573).

165994187 is an equidigital number, since it uses as much as digits as its factorization.

165994187 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 46572.

The product of its digits is 544320, while the sum is 50.

The square root of 165994187 is about 12883.8731365999. The cubic root of 165994187 is about 549.5800507818.

The spelling of 165994187 in words is "one hundred sixty-five million, nine hundred ninety-four thousand, one hundred eighty-seven".