13616322721 has 3 divisors (see below), whose sum is σ = 13616439411. Its totient is φ = 13616206032.

The previous prime is 13616322691. The next prime is 13616322739. The reversal of 13616322721 is 12722361631.

The square root of 13616322721 is 116689.

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

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 13112769121 + 503553600 = 114511^2 + 22440^2 .

It is not a de Polignac number, because 13616322721 - 2⁷ = 13616322593 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13616322791) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 58345 + ... + 175033.

It is an arithmetic number, because the mean of its divisors is an integer number (4538813137).

Almost surely, 2^13616322721 is an apocalyptic number.

13616322721 is the 116689-th square number.

13616322721 is the 58345-th centered octagonal number.

It is an amenable number.

13616322721 is a deficient number, since it is larger than the sum of its proper divisors (116690).

13616322721 is an frugal number, since it uses more digits than its factorization.

13616322721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 233378 (or 116689 counting only the distinct ones).

The product of its digits is 18144, while the sum is 34.

The spelling of 13616322721 in words is "thirteen billion, six hundred sixteen million, three hundred twenty-two thousand, seven hundred twenty-one".