2165649 has 4 divisors (see below), whose sum is σ = 2887536. Its totient is φ = 1443764.

The previous prime is 2165617. The next prime is 2165651. The reversal of 2165649 is 9465612.

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 2165649 - 2⁵ = 2165617 is a prime.

It is a D-number.

It is not an unprimeable number, because it can be changed into a prime (2165659) 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, 360939 + ... + 360944.

It is an arithmetic number, because the mean of its divisors is an integer number (721884).

2^2165649 is an apocalyptic number.

It is an amenable number.

2165649 is a deficient number, since it is larger than the sum of its proper divisors (721887).

2165649 is an equidigital number, since it uses as much as digits as its factorization.

2165649 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 721886.

The product of its digits is 12960, while the sum is 33.

The square root of 2165649 is about 1471.6144196086. The cubic root of 2165649 is about 129.3786722102.

Multiplying 2165649 by its sum of digits (33), we get a palindrome (71466417).

The spelling of 2165649 in words is "two million, one hundred sixty-five thousand, six hundred forty-nine".