689987 has 2 divisors, whose sum is σ = 689988. Its totient is φ = 689986.

The previous prime is 689981. The next prime is 690037. The reversal of 689987 is 789986.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 689987 - 2¹⁶ = 624451 is a prime.

It is a Chen prime.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (689981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344993 + 344994.

It is an arithmetic number, because the mean of its divisors is an integer number (344994).

2⁶⁸⁹⁹⁸⁷ is an apocalyptic number.

689987 is a deficient number, since it is larger than the sum of its proper divisors (1).

689987 is an equidigital number, since it uses as much as digits as its factorization.

689987 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 217728, while the sum is 47.

The square root of 689987 is about 830.6545611745. The cubic root of 689987 is about 88.3650042678.

Subtracting 689987 from its reverse (789986), we obtain a palindrome (99999).

The spelling of 689987 in words is "six hundred eighty-nine thousand, nine hundred eighty-seven".