820647 has 6 divisors (see below), whose sum is σ = 1185392. Its totient is φ = 547092.

The previous prime is 820643. The next prime is 820649. The reversal of 820647 is 746028.

820647 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 820647 - 2² = 820643 is a prime.

It is a super-2 number, since 2×820647² = 1346922997218, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 820647.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820643) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 45583 + ... + 45600.

2⁸²⁰⁶⁴⁷ is an apocalyptic number.

820647 is a deficient number, since it is larger than the sum of its proper divisors (364745).

820647 is a wasteful number, since it uses less digits than its factorization.

820647 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91189 (or 91186 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 820647 is about 905.8956893594. The cubic root of 820647 is about 93.6236270619.

The spelling of 820647 in words is "eight hundred twenty thousand, six hundred forty-seven".