165649889 has 4 divisors (see below), whose sum is σ = 169502256. Its totient is φ = 161797524.

The previous prime is 165649879. The next prime is 165649901. The reversal of 165649889 is 988946561.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 165649889 - 2⁴ = 165649873 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (165649829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1926119 + ... + 1926204.

It is an arithmetic number, because the mean of its divisors is an integer number (42375564).

Almost surely, 2^165649889 is an apocalyptic number.

It is an amenable number.

165649889 is a deficient number, since it is larger than the sum of its proper divisors (3852367).

165649889 is an equidigital number, since it uses as much as digits as its factorization.

165649889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3852366.

The product of its digits is 3732480, while the sum is 56.

The square root of 165649889 is about 12870.5046132621. The cubic root of 165649889 is about 549.1998160072.

The spelling of 165649889 in words is "one hundred sixty-five million, six hundred forty-nine thousand, eight hundred eighty-nine".