2311721309 has 2 divisors, whose sum is σ = 2311721310. Its totient is φ = 2311721308.

The previous prime is 2311721297. The next prime is 2311721369. The reversal of 2311721309 is 9031271132.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1900524025 + 411197284 = 43595^2 + 20278^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2311721309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2311721369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1155860654 + 1155860655.

It is an arithmetic number, because the mean of its divisors is an integer number (1155860655).

Almost surely, 2^2311721309 is an apocalyptic number.

It is an amenable number.

2311721309 is a deficient number, since it is larger than the sum of its proper divisors (1).

2311721309 is an equidigital number, since it uses as much as digits as its factorization.

2311721309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2268, while the sum is 29.

The square root of 2311721309 is about 48080.3630289955. The cubic root of 2311721309 is about 1322.2446711505.

The spelling of 2311721309 in words is "two billion, three hundred eleven million, seven hundred twenty-one thousand, three hundred nine".