721871305213 has 2 divisors, whose sum is σ = 721871305214. Its totient is φ = 721871305212.

The previous prime is 721871305189. The next prime is 721871305223. The reversal of 721871305213 is 312503178127.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 588414794724 + 133456510489 = 767082^2 + 365317^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-721871305213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (721871305223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 360935652606 + 360935652607.

It is an arithmetic number, because the mean of its divisors is an integer number (360935652607).

Almost surely, 2^721871305213 is an apocalyptic number.

It is an amenable number.

721871305213 is a deficient number, since it is larger than the sum of its proper divisors (1).

721871305213 is an equidigital number, since it uses as much as digits as its factorization.

721871305213 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 70560, while the sum is 40.

The spelling of 721871305213 in words is "seven hundred twenty-one billion, eight hundred seventy-one million, three hundred five thousand, two hundred thirteen".