12721637329 has 8 divisors (see below), whose sum is σ = 12982709160. Its totient is φ = 12461344896.

The previous prime is 12721637311. The next prime is 12721637363. The reversal of 12721637329 is 92373612721.

It can be written as a sum of positive squares in 4 ways, for example, as 3413246929 + 9308390400 = 58423^2 + 96480^2 .

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 12721637329 - 2⁵ = 12721637297 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12721437329) 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, 161814 + ... + 227215.

It is an arithmetic number, because the mean of its divisors is an integer number (1622838645).

Almost surely, 2^12721637329 is an apocalyptic number.

It is an amenable number.

12721637329 is a deficient number, since it is larger than the sum of its proper divisors (261071831).

12721637329 is an equidigital number, since it uses as much as digits as its factorization.

12721637329 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 389699.

The product of its digits is 190512, while the sum is 43.

The spelling of 12721637329 in words is "twelve billion, seven hundred twenty-one million, six hundred thirty-seven thousand, three hundred twenty-nine".