13218790729 has 3 divisors (see below), whose sum is σ = 13218905703. Its totient is φ = 13218675756.

The previous prime is 13218790709. The next prime is 13218790757. The reversal of 13218790729 is 92709781231.

The square root of 13218790729 is 114973.

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., 12885655225 + 333135504 = 113515^2 + 18252^2 .

It is not a de Polignac number, because 13218790729 - 2²⁷ = 13084573001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13218790709) 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 2 ways as a sum of consecutive naturals, for example, 57487 + ... + 172459.

It is an arithmetic number, because the mean of its divisors is an integer number (4406301901).

Almost surely, 2^13218790729 is an apocalyptic number.

13218790729 is the 114973-rd square number.

13218790729 is the 57487-th centered octagonal number.

It is an amenable number.

13218790729 is a deficient number, since it is larger than the sum of its proper divisors (114974).

13218790729 is an frugal number, since it uses more digits than its factorization.

13218790729 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229946 (or 114973 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 49.

Multiplying 13218790729 by its sum of digits (49), we get a square (647720745721 = 804811²).

The spelling of 13218790729 in words is "thirteen billion, two hundred eighteen million, seven hundred ninety thousand, seven hundred twenty-nine".