12720736521 has 24 divisors (see below), whose sum is σ = 18488321280. Its totient is φ = 8428056000.

The previous prime is 12720736487. The next prime is 12720736577. The reversal of 12720736521 is 12563702721.

12720736521 is a `hidden beast` number, since 1 + 272 + 0 + 7 + 365 + 21 = 666.

It is not a de Polignac number, because 12720736521 - 2⁹ = 12720736009 is a prime.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (12720736121) 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, 1114996 + ... + 1126346.

It is an arithmetic number, because the mean of its divisors is an integer number (770346720).

Almost surely, 2^12720736521 is an apocalyptic number.

It is an amenable number.

12720736521 is a deficient number, since it is larger than the sum of its proper divisors (5767584759).

12720736521 is a wasteful number, since it uses less digits than its factorization.

12720736521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12117 (or 12114 counting only the distinct ones).

The product of its (nonzero) digits is 35280, while the sum is 36.

The spelling of 12720736521 in words is "twelve billion, seven hundred twenty million, seven hundred thirty-six thousand, five hundred twenty-one".