13739445721 has 2 divisors, whose sum is σ = 13739445722. Its totient is φ = 13739445720.

The previous prime is 13739445719. The next prime is 13739445743. The reversal of 13739445721 is 12754493731.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7570914121 + 6168531600 = 87011^2 + 78540^2 .

It is a cyclic number.

It is not a de Polignac number, because 13739445721 - 2¹ = 13739445719 is a prime.

Together with 13739445719, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (13739448721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6869722860 + 6869722861.

It is an arithmetic number, because the mean of its divisors is an integer number (6869722861).

Almost surely, 2^13739445721 is an apocalyptic number.

It is an amenable number.

13739445721 is a deficient number, since it is larger than the sum of its proper divisors (1).

13739445721 is an equidigital number, since it uses as much as digits as its factorization.

13739445721 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 635040, while the sum is 46.

The spelling of 13739445721 in words is "thirteen billion, seven hundred thirty-nine million, four hundred forty-five thousand, seven hundred twenty-one".