12744157661 has 4 divisors (see below), whose sum is σ = 13493814012. Its totient is φ = 11994501312.

The previous prime is 12744157651. The next prime is 12744157681. The reversal of 12744157661 is 16675144721.

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

It can be written as a sum of positive squares in 2 ways, for example, as 10814752036 + 1929405625 = 103994^2 + 43925^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12744157661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12744157651) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 374828150 + ... + 374828183.

It is an arithmetic number, because the mean of its divisors is an integer number (3373453503).

Almost surely, 2^12744157661 is an apocalyptic number.

It is an amenable number.

12744157661 is a deficient number, since it is larger than the sum of its proper divisors (749656351).

12744157661 is an equidigital number, since it uses as much as digits as its factorization.

12744157661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 749656350.

The product of its digits is 282240, while the sum is 44.

The spelling of 12744157661 in words is "twelve billion, seven hundred forty-four million, one hundred fifty-seven thousand, six hundred sixty-one".