13268505721 has 9 divisors (see below), whose sum is σ = 13388566149. Its totient is φ = 13149515484.

The previous prime is 13268505689. The next prime is 13268505779. The reversal of 13268505721 is 12750586231.

The square root of 13268505721 is 115189.

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

It is not a de Polignac number, because 13268505721 - 2⁵ = 13268505689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13268505781) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 14628550 + ... + 14629456.

It is an arithmetic number, because the mean of its divisors is an integer number (1487618461).

Almost surely, 2^13268505721 is an apocalyptic number.

13268505721 is the 115189-th square number.

13268505721 is the 57595-th centered octagonal number.

It is an amenable number.

13268505721 is a deficient number, since it is larger than the sum of its proper divisors (120060428).

13268505721 is an frugal number, since it uses more digits than its factorization.

13268505721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2068 (or 1034 counting only the distinct ones).

The product of its (nonzero) digits is 100800, while the sum is 40.

The spelling of 13268505721 in words is "thirteen billion, two hundred sixty-eight million, five hundred five thousand, seven hundred twenty-one".