691384823 has 2 divisors, whose sum is σ = 691384824. Its totient is φ = 691384822.

The previous prime is 691384783. The next prime is 691384867. The reversal of 691384823 is 328483196.

It is an a-pointer prime, because the next prime (691384867) can be obtained adding 691384823 to its sum of digits (44).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691384823 - 2⁸ = 691384567 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691384873) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345692411 + 345692412.

It is an arithmetic number, because the mean of its divisors is an integer number (345692412).

Almost surely, 2^691384823 is an apocalyptic number.

691384823 is a deficient number, since it is larger than the sum of its proper divisors (1).

691384823 is an equidigital number, since it uses as much as digits as its factorization.

691384823 is an evil number, because the sum of its binary digits is even.

The product of its digits is 248832, while the sum is 44.

The square root of 691384823 is about 26294.1975158018. The cubic root of 691384823 is about 884.2463597980.

The spelling of 691384823 in words is "six hundred ninety-one million, three hundred eighty-four thousand, eight hundred twenty-three".