688887891 has 6 divisors (see below), whose sum is σ = 995060300. Its totient is φ = 459258588.

The previous prime is 688887877. The next prime is 688887893. The reversal of 688887891 is 198788886.

It is a happy number.

It is not a de Polignac number, because 688887891 - 2⁶ = 688887827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688887893) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 38271541 + ... + 38271558.

Almost surely, 2^688887891 is an apocalyptic number.

688887891 is a deficient number, since it is larger than the sum of its proper divisors (306172409).

688887891 is a wasteful number, since it uses less digits than its factorization.

688887891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76543105 (or 76543102 counting only the distinct ones).

The product of its digits is 12386304, while the sum is 63.

The square root of 688887891 is about 26246.6739035635. The cubic root of 688887891 is about 883.1805923476.

The spelling of 688887891 in words is "six hundred eighty-eight million, eight hundred eighty-seven thousand, eight hundred ninety-one".