12615436447721 has 8 divisors (see below), whose sum is σ = 12664672252584. Its totient is φ = 12566201794560.

The previous prime is 12615436447703. The next prime is 12615436447723. The reversal of 12615436447721 is 12774463451621.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 369951031696 + 12245485416025 = 608236^2 + 3499355^2 .

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 12615436447721 - 2¹⁸ = 12615436185577 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12615436447723) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26521301 + ... + 26992781.

It is an arithmetic number, because the mean of its divisors is an integer number (1583084031573).

Almost surely, 2^{12615436447721} is an apocalyptic number.

It is an amenable number.

12615436447721 is a deficient number, since it is larger than the sum of its proper divisors (49235804863).

12615436447721 is a wasteful number, since it uses less digits than its factorization.

12615436447721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 575851.

The product of its digits is 6773760, while the sum is 53.

The spelling of 12615436447721 in words is "twelve trillion, six hundred fifteen billion, four hundred thirty-six million, four hundred forty-seven thousand, seven hundred twenty-one".