820855290 has 64 divisors (see below), whose sum is σ = 2077200000. Its totient is φ = 207028224.

The previous prime is 820855279. The next prime is 820855313. The reversal of 820855290 is 92558028.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 656586 + ... + 657834.

It is an arithmetic number, because the mean of its divisors is an integer number (32456250).

Almost surely, 2^820855290 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 820855290, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1038600000).

820855290 is an abundant number, since it is smaller than the sum of its proper divisors (1256344710).

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

820855290 is a wasteful number, since it uses less digits than its factorization.

820855290 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2431.

The product of its (nonzero) digits is 57600, while the sum is 39.

The square root of 820855290 is about 28650.5722455940. The cubic root of 820855290 is about 936.3154732309.

The spelling of 820855290 in words is "eight hundred twenty million, eight hundred fifty-five thousand, two hundred ninety".