291521997313 has 2 divisors, whose sum is σ = 291521997314. Its totient is φ = 291521997312.

The previous prime is 291521997287. The next prime is 291521997331. The reversal of 291521997313 is 313799125192.

Together with next prime (291521997331) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 152231068224 + 139290929089 = 390168^2 + 373217^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-291521997313 is a prime.

It is not a weakly prime, because it can be changed into another prime (291521997353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 145760998656 + 145760998657.

It is an arithmetic number, because the mean of its divisors is an integer number (145760998657).

Almost surely, 2^291521997313 is an apocalyptic number.

It is an amenable number.

291521997313 is a deficient number, since it is larger than the sum of its proper divisors (1).

291521997313 is an equidigital number, since it uses as much as digits as its factorization.

291521997313 is an evil number, because the sum of its binary digits is even.

The product of its digits is 918540, while the sum is 52.

The spelling of 291521997313 in words is "two hundred ninety-one billion, five hundred twenty-one million, nine hundred ninety-seven thousand, three hundred thirteen".