689851 has 2 divisors, whose sum is σ = 689852. Its totient is φ = 689850.

The previous prime is 689831. The next prime is 689867. The reversal of 689851 is 158986.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 689851 - 2⁷ = 689723 is a prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 689851.

It is not a weakly prime, because it can be changed into another prime (689831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 344925 + 344926.

It is an arithmetic number, because the mean of its divisors is an integer number (344926).

2⁶⁸⁹⁸⁵¹ is an apocalyptic number.

689851 is a deficient number, since it is larger than the sum of its proper divisors (1).

689851 is an equidigital number, since it uses as much as digits as its factorization.

689851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 37.

The square root of 689851 is about 830.5726939889. The cubic root of 689851 is about 88.3591981534.

It can be divided in two parts, 68985 and 1, that added together give a palindrome (68986).

The spelling of 689851 in words is "six hundred eighty-nine thousand, eight hundred fifty-one".