687911691 has 4 divisors (see below), whose sum is σ = 917215592. Its totient is φ = 458607792.

The previous prime is 687911689. The next prime is 687911699. The reversal of 687911691 is 196119786.

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

It is not a de Polignac number, because 687911691 - 2¹ = 687911689 is a prime.

It is a super-2 number, since 2×687911691² = 946444989228958962, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 687911691.

It is not an unprimeable number, because it can be changed into a prime (687911699) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 114651946 + ... + 114651951.

It is an arithmetic number, because the mean of its divisors is an integer number (229303898).

Almost surely, 2^687911691 is an apocalyptic number.

687911691 is a deficient number, since it is larger than the sum of its proper divisors (229303901).

687911691 is a wasteful number, since it uses less digits than its factorization.

687911691 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 229303900.

The product of its digits is 163296, while the sum is 48.

The square root of 687911691 is about 26228.0706686557. The cubic root of 687911691 is about 882.7632199067.

The spelling of 687911691 in words is "six hundred eighty-seven million, nine hundred eleven thousand, six hundred ninety-one".