691933687 has 4 divisors (see below), whose sum is σ = 692221680. Its totient is φ = 691645696.

The previous prime is 691933681. The next prime is 691933699. The reversal of 691933687 is 786339196.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 691933687 - 2¹⁵ = 691900919 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691933681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 140362 + ... + 145207.

It is an arithmetic number, because the mean of its divisors is an integer number (173055420).

Almost surely, 2^691933687 is an apocalyptic number.

691933687 is a deficient number, since it is larger than the sum of its proper divisors (287993).

691933687 is a wasteful number, since it uses less digits than its factorization.

691933687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 287992.

The product of its digits is 1469664, while the sum is 52.

The square root of 691933687 is about 26304.6324247270. The cubic root of 691933687 is about 884.4802877090.

The spelling of 691933687 in words is "six hundred ninety-one million, nine hundred thirty-three thousand, six hundred eighty-seven".