820817847 has 16 divisors (see below), whose sum is σ = 1216519680. Its totient is φ = 546989976.

The previous prime is 820817843. The next prime is 820817857. The reversal of 820817847 is 748718028.

It is not a de Polignac number, because 820817847 - 2² = 820817843 is a prime.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820817843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 87528 + ... + 96450.

It is an arithmetic number, because the mean of its divisors is an integer number (76032480).

Almost surely, 2^820817847 is an apocalyptic number.

820817847 is a deficient number, since it is larger than the sum of its proper divisors (395701833).

820817847 is a wasteful number, since it uses less digits than its factorization.

820817847 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12339 (or 12333 counting only the distinct ones).

The product of its (nonzero) digits is 200704, while the sum is 45.

The square root of 820817847 is about 28649.9187956964. The cubic root of 820817847 is about 936.3012364570.

It can be divided in two parts, 8208178 and 47, that added together give a square (8208225 = 2865²).

The spelling of 820817847 in words is "eight hundred twenty million, eight hundred seventeen thousand, eight hundred forty-seven".