165620225 has 24 divisors (see below), whose sum is σ = 209257440. Its totient is φ = 130014720.

The previous prime is 165620179. The next prime is 165620227. The reversal of 165620225 is 522026561.

It is not a de Polignac number, because 165620225 - 2⁸ = 165619969 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (165620227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 395066 + ... + 395484.

It is an arithmetic number, because the mean of its divisors is an integer number (8719060).

Almost surely, 2^165620225 is an apocalyptic number.

It is an amenable number.

165620225 is a deficient number, since it is larger than the sum of its proper divisors (43637215).

165620225 is a wasteful number, since it uses less digits than its factorization.

165620225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 689 (or 684 counting only the distinct ones).

The product of its (nonzero) digits is 7200, while the sum is 29.

The square root of 165620225 is about 12869.3521592969. The cubic root of 165620225 is about 549.1670311258.

Adding to 165620225 its reverse (522026561), we get a palindrome (687646786).

The spelling of 165620225 in words is "one hundred sixty-five million, six hundred twenty thousand, two hundred twenty-five".