691867811 has 2 divisors, whose sum is σ = 691867812. Its totient is φ = 691867810.

The previous prime is 691867769. The next prime is 691867817. The reversal of 691867811 is 118768196.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691867811 - 2⁶ = 691867747 is a prime.

It is not a weakly prime, because it can be changed into another prime (691867817) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345933905 + 345933906.

It is an arithmetic number, because the mean of its divisors is an integer number (345933906).

Almost surely, 2^691867811 is an apocalyptic number.

691867811 is a deficient number, since it is larger than the sum of its proper divisors (1).

691867811 is an equidigital number, since it uses as much as digits as its factorization.

691867811 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 47.

The square root of 691867811 is about 26303.3802200402. The cubic root of 691867811 is about 884.4522176431.

The spelling of 691867811 in words is "six hundred ninety-one million, eight hundred sixty-seven thousand, eight hundred eleven".