165121664 has 16 divisors (see below), whose sum is σ = 328953570. Its totient is φ = 82560768.

The previous prime is 165121661. The next prime is 165121681. The reversal of 165121664 is 466121561.

It can be written as a sum of positive squares in only one way, i.e., 153561664 + 11560000 = 12392^2 + 3400^2 .

It is a tau number, because it is divible by the number of its divisors (16).

It is a Harshad number since it is a multiple of its sum of digits (32).

It is a self number, because there is not a number n which added to its sum of digits gives 165121664.

It is not an unprimeable number, because it can be changed into a prime (165121661) 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 as a sum of consecutive naturals, namely, 644879 + ... + 645134.

Almost surely, 2^165121664 is an apocalyptic number.

It is an amenable number.

165121664 is a deficient number, since it is larger than the sum of its proper divisors (163831906).

165121664 is an equidigital number, since it uses as much as digits as its factorization.

165121664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1290027 (or 1290015 counting only the distinct ones).

The product of its digits is 8640, while the sum is 32.

The square root of 165121664 is about 12849.9674707759. The cubic root of 165121664 is about 548.6154309115.

The spelling of 165121664 in words is "one hundred sixty-five million, one hundred twenty-one thousand, six hundred sixty-four".