12721261553 has 72 divisors (see below), whose sum is σ = 17435291328. Its totient is φ = 9081072000.

The previous prime is 12721261549. The next prime is 12721261591. The reversal of 12721261553 is 35516212721.

It is not a de Polignac number, because 12721261553 - 2² = 12721261549 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12721264553) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 25908638 + ... + 25909128.

It is an arithmetic number, because the mean of its divisors is an integer number (242156824).

Almost surely, 2^12721261553 is an apocalyptic number.

12721261553 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

12721261553 is a deficient number, since it is larger than the sum of its proper divisors (4714029775).

12721261553 is a wasteful number, since it uses less digits than its factorization.

12721261553 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 727 (or 703 counting only the distinct ones).

The product of its digits is 25200, while the sum is 35.

The spelling of 12721261553 in words is "twelve billion, seven hundred twenty-one million, two hundred sixty-one thousand, five hundred fifty-three".