691026913 has 2 divisors, whose sum is σ = 691026914. Its totient is φ = 691026912.

The previous prime is 691026907. The next prime is 691026923. The reversal of 691026913 is 319620196.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 608707584 + 82319329 = 24672^2 + 9073^2 .

It is a cyclic number.

It is not a de Polignac number, because 691026913 - 2²⁵ = 657472481 is a prime.

It is not a weakly prime, because it can be changed into another prime (691026923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345513456 + 345513457.

It is an arithmetic number, because the mean of its divisors is an integer number (345513457).

Almost surely, 2^691026913 is an apocalyptic number.

It is an amenable number.

691026913 is a deficient number, since it is larger than the sum of its proper divisors (1).

691026913 is an equidigital number, since it uses as much as digits as its factorization.

691026913 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 691026913 is about 26287.3907605909. The cubic root of 691026913 is about 884.0937505077.

The spelling of 691026913 in words is "six hundred ninety-one million, twenty-six thousand, nine hundred thirteen".