721136337689 has 2 divisors, whose sum is σ = 721136337690. Its totient is φ = 721136337688.

The previous prime is 721136337671. The next prime is 721136337703. The reversal of 721136337689 is 986733631127.

721136337689 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 652548918025 + 68587419664 = 807805^2 + 261892^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721136337689 is a prime.

It is not a weakly prime, because it can be changed into another prime (721136337589) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360568168844 + 360568168845.

It is an arithmetic number, because the mean of its divisors is an integer number (360568168845).

Almost surely, 2^721136337689 is an apocalyptic number.

It is an amenable number.

721136337689 is a deficient number, since it is larger than the sum of its proper divisors (1).

721136337689 is an equidigital number, since it uses as much as digits as its factorization.

721136337689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6858432, while the sum is 56.

The spelling of 721136337689 in words is "seven hundred twenty-one billion, one hundred thirty-six million, three hundred thirty-seven thousand, six hundred eighty-nine".