691651691 has 2 divisors, whose sum is σ = 691651692. Its totient is φ = 691651690.

The previous prime is 691651679. The next prime is 691651703. The reversal of 691651691 is 196156196.

691651691 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (691651679) and next prime (691651703).

It is a cyclic number.

It is not a de Polignac number, because 691651691 - 2⁶ = 691651627 is a prime.

It is not a weakly prime, because it can be changed into another prime (691651601) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345825845 + 345825846.

It is an arithmetic number, because the mean of its divisors is an integer number (345825846).

Almost surely, 2^691651691 is an apocalyptic number.

691651691 is a deficient number, since it is larger than the sum of its proper divisors (1).

691651691 is an equidigital number, since it uses as much as digits as its factorization.

691651691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 87480, while the sum is 44.

The square root of 691651691 is about 26299.2716819307. The cubic root of 691651691 is about 884.3601154058.

The spelling of 691651691 in words is "six hundred ninety-one million, six hundred fifty-one thousand, six hundred ninety-one".