688287989 has 2 divisors, whose sum is σ = 688287990. Its totient is φ = 688287988.

The previous prime is 688287967. The next prime is 688288039. The reversal of 688287989 is 989782886.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 584043889 + 104244100 = 24167^2 + 10210^2 .

It is a cyclic number.

It is not a de Polignac number, because 688287989 - 2¹⁶ = 688222453 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (688287889) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344143994 + 344143995.

It is an arithmetic number, because the mean of its divisors is an integer number (344143995).

Almost surely, 2^688287989 is an apocalyptic number.

It is an amenable number.

688287989 is a deficient number, since it is larger than the sum of its proper divisors (1).

688287989 is an equidigital number, since it uses as much as digits as its factorization.

688287989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 27869184, while the sum is 65.

The square root of 688287989 is about 26235.2432616890. The cubic root of 688287989 is about 882.9241521346.

The spelling of 688287989 in words is "six hundred eighty-eight million, two hundred eighty-seven thousand, nine hundred eighty-nine".