12720317856521 has 16 divisors (see below), whose sum is σ = 13894532583360. Its totient is φ = 11549077485120.

The previous prime is 12720317856497. The next prime is 12720317856569. The reversal of 12720317856521 is 12565871302721.

12720317856521 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 12720317856521 - 2³⁸ = 12445439949577 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 12720317856521.

It is not an unprimeable number, because it can be changed into a prime (12720317856121) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 66234191 + ... + 66425963.

It is an arithmetic number, because the mean of its divisors is an integer number (868408286460).

Almost surely, 2^{12720317856521} is an apocalyptic number.

12720317856521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12720317856521 is a deficient number, since it is larger than the sum of its proper divisors (1174214726839).

12720317856521 is a wasteful number, since it uses less digits than its factorization.

12720317856521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199496.

The product of its (nonzero) digits is 1411200, while the sum is 50.

The spelling of 12720317856521 in words is "twelve trillion, seven hundred twenty billion, three hundred seventeen million, eight hundred fifty-six thousand, five hundred twenty-one".