689978 has 16 divisors (see below), whose sum is σ = 1083456. Its totient is φ = 329280.

The previous prime is 689963. The next prime is 689981. The reversal of 689978 is 879986.

689978 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6050 + ... + 6162.

It is an arithmetic number, because the mean of its divisors is an integer number (67716).

2⁶⁸⁹⁹⁷⁸ is an apocalyptic number.

689978 is a deficient number, since it is larger than the sum of its proper divisors (393478).

689978 is a wasteful number, since it uses less digits than its factorization.

689978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229.

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

The square root of 689978 is about 830.6491437424. The cubic root of 689978 is about 88.3646200632.

The spelling of 689978 in words is "six hundred eighty-nine thousand, nine hundred seventy-eight".