691783691 has 2 divisors, whose sum is σ = 691783692. Its totient is φ = 691783690.

The previous prime is 691783681. The next prime is 691783721. The reversal of 691783691 is 196387196.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 691783691 - 2¹⁸ = 691521547 is a prime.

It is not a weakly prime, because it can be changed into another prime (691783681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345891845 + 345891846.

It is an arithmetic number, because the mean of its divisors is an integer number (345891846).

Almost surely, 2^691783691 is an apocalyptic number.

691783691 is a deficient number, since it is larger than the sum of its proper divisors (1).

691783691 is an equidigital number, since it uses as much as digits as its factorization.

691783691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 489888, while the sum is 50.

The square root of 691783691 is about 26301.7811374059. The cubic root of 691783691 is about 884.4163711346.

The spelling of 691783691 in words is "six hundred ninety-one million, seven hundred eighty-three thousand, six hundred ninety-one".