1688008891 has 2 divisors, whose sum is σ = 1688008892. Its totient is φ = 1688008890.

The previous prime is 1688008873. The next prime is 1688008919. The reversal of 1688008891 is 1988008861.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1688008891 - 2⁹ = 1688008379 is a prime.

1688008891 is a strobogrammatic number because it is the same when read upside-down.

It is not a weakly prime, because it can be changed into another prime (1688008391) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 844004445 + 844004446.

It is an arithmetic number, because the mean of its divisors is an integer number (844004446).

Almost surely, 2^1688008891 is an apocalyptic number.

1688008891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1688008891 is an equidigital number, since it uses as much as digits as its factorization.

1688008891 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 221184, while the sum is 49.

The square root of 1688008891 is about 41085.3853699828. The cubic root of 1688008891 is about 1190.6704531124.

The spelling of 1688008891 in words is "one billion, six hundred eighty-eight million, eight thousand, eight hundred ninety-one".