12861626588721 has 45 divisors (see below), whose sum is σ = 19695114020923. Its totient is φ = 8364424871520.

The previous prime is 12861626588719. The next prime is 12861626588729. The reversal of 12861626588721 is 12788562616821.

The square root of 12861626588721 is 3586311.

It is a perfect power (a square), and thus also a powerful number.

12861626588721 is a `hidden beast` number, since 1 + 2 + 8 + 6 + 1 + 6 + 26 + 588 + 7 + 21 = 666.

It can be written as a sum of positive squares in only one way, i.e., 619745243121 + 12241881345600 = 787239^2 + 3498840^2 .

It is not a de Polignac number, because 12861626588721 - 2¹ = 12861626588719 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12861626588729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 1323343900 + ... + 1323353618.

Almost surely, 2^{12861626588721} is an apocalyptic number.

12861626588721 is the 3586311-st square number.

12861626588721 is the 1793156-th centered octagonal number.

It is an amenable number.

12861626588721 is a deficient number, since it is larger than the sum of its proper divisors (6833487432202).

12861626588721 is an frugal number, since it uses more digits than its factorization.

12861626588721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19532 (or 9763 counting only the distinct ones).

The product of its digits is 30965760, while the sum is 63.

The spelling of 12861626588721 in words is "twelve trillion, eight hundred sixty-one billion, six hundred twenty-six million, five hundred eighty-eight thousand, seven hundred twenty-one".