688888891 has 2 divisors, whose sum is σ = 688888892. Its totient is φ = 688888890.

The previous prime is 688888883. The next prime is 688888901. The reversal of 688888891 is 198888886.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 688888891 - 2³ = 688888883 is a prime.

It is not a weakly prime, because it can be changed into another prime (688888831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344444445 + 344444446.

It is an arithmetic number, because the mean of its divisors is an integer number (344444446).

Almost surely, 2^688888891 is an apocalyptic number.

688888891 is a deficient number, since it is larger than the sum of its proper divisors (1).

688888891 is an equidigital number, since it uses as much as digits as its factorization.

688888891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 14155776, while the sum is 64.

The square root of 688888891 is about 26246.6929535894. The cubic root of 688888891 is about 883.1810196934.

The spelling of 688888891 in words is "six hundred eighty-eight million, eight hundred eighty-eight thousand, eight hundred ninety-one".