820664460 has 672 divisors, whose sum is σ = 3490324992. Its totient is φ = 156764160.

The previous prime is 820664447. The next prime is 820664483. The reversal of 820664460 is 64466028.

It is a happy number.

820664460 is a `hidden beast` number, since 8 + 2 + 0 + 6 + 644 + 6 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

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 223 ways as a sum of consecutive naturals, for example, 19085199 + ... + 19085241.

It is an arithmetic number, because the mean of its divisors is an integer number (5193936).

Almost surely, 2^820664460 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 820664460, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1745162496).

820664460 is an abundant number, since it is smaller than the sum of its proper divisors (2669660532).

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

820664460 is a wasteful number, since it uses less digits than its factorization.

820664460 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 36.

The square root of 820664460 is about 28647.2417520431. The cubic root of 820664460 is about 936.2429103273.

The spelling of 820664460 in words is "eight hundred twenty million, six hundred sixty-four thousand, four hundred sixty".