820650864 has 80 divisors (see below), whose sum is σ = 2316708864. Its totient is φ = 248256000.

The previous prime is 820650851. The next prime is 820650881. The reversal of 820650864 is 468056028.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 454764 + ... + 456564.

Almost surely, 2^820650864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820650864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1158354432).

820650864 is an abundant number, since it is smaller than the sum of its proper divisors (1496058000).

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

820650864 is a wasteful number, since it uses less digits than its factorization.

820650864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2686 (or 2680 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 39.

The square root of 820650864 is about 28647.0044507275. The cubic root of 820650864 is about 936.2377400336.

The spelling of 820650864 in words is "eight hundred twenty million, six hundred fifty thousand, eight hundred sixty-four".