12721815705 has 16 divisors (see below), whose sum is σ = 20699904960. Its totient is φ = 6669968448.

The previous prime is 12721815703. The next prime is 12721815721. The reversal of 12721815705 is 50751812721.

It is not a de Polignac number, because 12721815705 - 2¹ = 12721815703 is a prime.

It is not an unprimeable number, because it can be changed into a prime (12721815703) 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, 7186582 + ... + 7188351.

It is an arithmetic number, because the mean of its divisors is an integer number (1293744060).

Almost surely, 2^12721815705 is an apocalyptic number.

12721815705 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

12721815705 is a deficient number, since it is larger than the sum of its proper divisors (7978089255).

12721815705 is a wasteful number, since it uses less digits than its factorization.

12721815705 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14375000.

The product of its (nonzero) digits is 39200, while the sum is 39.

The spelling of 12721815705 in words is "twelve billion, seven hundred twenty-one million, eight hundred fifteen thousand, seven hundred five".