12261371665 has 8 divisors (see below), whose sum is σ = 14812396200. Its totient is φ = 9743263872.

The previous prime is 12261371663. The next prime is 12261371671. The reversal of 12261371665 is 56617316221.

It can be written as a sum of positive squares in 4 ways, for example, as 1815100816 + 10446270849 = 42604^2 + 102207^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12261371665 - 2¹ = 12261371663 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12261371663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8228364 + ... + 8229853.

It is an arithmetic number, because the mean of its divisors is an integer number (1851549525).

Almost surely, 2^12261371665 is an apocalyptic number.

It is an amenable number.

12261371665 is a deficient number, since it is larger than the sum of its proper divisors (2551024535).

12261371665 is a wasteful number, since it uses less digits than its factorization.

12261371665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16458371.

The product of its digits is 90720, while the sum is 40.

Adding to 12261371665 its reverse (56617316221), we get a palindrome (68878687886).

The spelling of 12261371665 in words is "twelve billion, two hundred sixty-one million, three hundred seventy-one thousand, six hundred sixty-five".