691340420591 has 2 divisors, whose sum is σ = 691340420592. Its totient is φ = 691340420590.

The previous prime is 691340420581. The next prime is 691340420599. The reversal of 691340420591 is 195024043196.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-691340420591 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691340420599) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345670210295 + 345670210296.

It is an arithmetic number, because the mean of its divisors is an integer number (345670210296).

Almost surely, 2^691340420591 is an apocalyptic number.

691340420591 is a deficient number, since it is larger than the sum of its proper divisors (1).

691340420591 is an equidigital number, since it uses as much as digits as its factorization.

691340420591 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 233280, while the sum is 44.

The spelling of 691340420591 in words is "six hundred ninety-one billion, three hundred forty million, four hundred twenty thousand, five hundred ninety-one".