12664220165 has 4 divisors (see below), whose sum is σ = 15197064204. Its totient is φ = 10131376128.

The previous prime is 12664220147. The next prime is 12664220183. The reversal of 12664220165 is 56102246621.

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

It is an interprime number because it is at equal distance from previous prime (12664220147) and next prime (12664220183).

It can be written as a sum of positive squares in 2 ways, for example, as 6459979876 + 6204240289 = 80374^2 + 78767^2 .

It is a cyclic number.

It is not a de Polignac number, because 12664220165 - 2²⁰ = 12663171589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1266422012 + ... + 1266422021.

It is an arithmetic number, because the mean of its divisors is an integer number (3799266051).

Almost surely, 2^12664220165 is an apocalyptic number.

It is an amenable number.

12664220165 is a deficient number, since it is larger than the sum of its proper divisors (2532844039).

12664220165 is an equidigital number, since it uses as much as digits as its factorization.

12664220165 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2532844038.

The product of its (nonzero) digits is 34560, while the sum is 35.

Adding to 12664220165 its reverse (56102246621), we get a palindrome (68766466786).

The spelling of 12664220165 in words is "twelve billion, six hundred sixty-four million, two hundred twenty thousand, one hundred sixty-five".