820866312 has 320 divisors, whose sum is σ = 2776456320. Its totient is φ = 221709312.

The previous prime is 820866271. The next prime is 820866337. The reversal of 820866312 is 213668028.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 11244708 + ... + 11244780.

It is an arithmetic number, because the mean of its divisors is an integer number (8676426).

Almost surely, 2^820866312 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 820866312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1388228160).

820866312 is an abundant number, since it is smaller than the sum of its proper divisors (1955590008).

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

820866312 is a wasteful number, since it uses less digits than its factorization.

820866312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 820866312 is about 28650.7645971272. The cubic root of 820866312 is about 936.3196639910.

The spelling of 820866312 in words is "eight hundred twenty million, eight hundred sixty-six thousand, three hundred twelve".