691924687 has 2 divisors, whose sum is σ = 691924688. Its totient is φ = 691924686.

The previous prime is 691924661. The next prime is 691924703. The reversal of 691924687 is 786429196.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691924687 - 2⁷ = 691924559 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691924637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345962343 + 345962344.

It is an arithmetic number, because the mean of its divisors is an integer number (345962344).

Almost surely, 2^691924687 is an apocalyptic number.

691924687 is a deficient number, since it is larger than the sum of its proper divisors (1).

691924687 is an equidigital number, since it uses as much as digits as its factorization.

691924687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 52.

The square root of 691924687 is about 26304.4613516415. The cubic root of 691924687 is about 884.4764528727.

The spelling of 691924687 in words is "six hundred ninety-one million, nine hundred twenty-four thousand, six hundred eighty-seven".