691665967 has 2 divisors, whose sum is σ = 691665968. Its totient is φ = 691665966.

The previous prime is 691665907. The next prime is 691666013. The reversal of 691665967 is 769566196.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691665967 - 2¹¹ = 691663919 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691665907) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345832983 + 345832984.

It is an arithmetic number, because the mean of its divisors is an integer number (345832984).

Almost surely, 2^691665967 is an apocalyptic number.

691665967 is a deficient number, since it is larger than the sum of its proper divisors (1).

691665967 is an equidigital number, since it uses as much as digits as its factorization.

691665967 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3674160, while the sum is 55.

The square root of 691665967 is about 26299.5430948905. The cubic root of 691665967 is about 884.3661998933.

The spelling of 691665967 in words is "six hundred ninety-one million, six hundred sixty-five thousand, nine hundred sixty-seven".