820668 has 12 divisors (see below), whose sum is σ = 1914920. Its totient is φ = 273552.

The previous prime is 820657. The next prime is 820679. The reversal of 820668 is 866028.

820668 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (820657) and next prime (820679).

It is a tau number, because it is divible by the number of its divisors (12).

It is an Ulam number.

It is a nialpdrome in base 7.

It is a congruent number.

It is an unprimeable number.

820668 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34183 + ... + 34206.

2⁸²⁰⁶⁶⁸ is an apocalyptic number.

It is an amenable number.

820668 is an abundant number, since it is smaller than the sum of its proper divisors (1094252).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

820668 is a wasteful number, since it uses less digits than its factorization.

820668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68396 (or 68394 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 820668 is about 905.9072800237. The cubic root of 820668 is about 93.6244256511.

The spelling of 820668 in words is "eight hundred twenty thousand, six hundred sixty-eight".