820644807 has 16 divisors (see below), whose sum is σ = 1169618688. Its totient is φ = 510544320.

The previous prime is 820644787. The next prime is 820644829. The reversal of 820644807 is 708446028.

820644807 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 820644807 - 2¹⁰ = 820643783 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820644607) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 142213 + ... + 147870.

It is an arithmetic number, because the mean of its divisors is an integer number (73101168).

Almost surely, 2^820644807 is an apocalyptic number.

820644807 is a deficient number, since it is larger than the sum of its proper divisors (348973881).

820644807 is a wasteful number, since it uses less digits than its factorization.

820644807 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 290150.

The product of its (nonzero) digits is 86016, while the sum is 39.

The square root of 820644807 is about 28646.8987326726. The cubic root of 820644807 is about 936.2354366562.

The spelling of 820644807 in words is "eight hundred twenty million, six hundred forty-four thousand, eight hundred seven".