13221811665 has 24 divisors (see below), whose sum is σ = 22951027008. Its totient is φ = 7041411360.

The previous prime is 13221811663. The next prime is 13221811697. The reversal of 13221811665 is 56611812231.

It is not a de Polignac number, because 13221811665 - 2¹ = 13221811663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (13221811663) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 181509 + ... + 243698.

It is an arithmetic number, because the mean of its divisors is an integer number (956292792).

Almost surely, 2^13221811665 is an apocalyptic number.

13221811665 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

13221811665 is a deficient number, since it is larger than the sum of its proper divisors (9729215343).

13221811665 is a wasteful number, since it uses less digits than its factorization.

13221811665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425909 (or 425906 counting only the distinct ones).

The product of its digits is 17280, while the sum is 36.

The spelling of 13221811665 in words is "thirteen billion, two hundred twenty-one million, eight hundred eleven thousand, six hundred sixty-five".