821345856 has 28 divisors (see below), whose sum is σ = 2173144752. Its totient is φ = 273781888.

The previous prime is 821345809. The next prime is 821345887. The reversal of 821345856 is 658543128.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2138730 + ... + 2139113.

Almost surely, 2^821345856 is an apocalyptic number.

It is an amenable number.

821345856 is an abundant number, since it is smaller than the sum of its proper divisors (1351798896).

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

821345856 is a wasteful number, since it uses less digits than its factorization.

821345856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4277858 (or 4277848 counting only the distinct ones).

The product of its digits is 230400, while the sum is 42.

The square root of 821345856 is about 28659.1321571327. The cubic root of 821345856 is about 936.5019588273.

It can be divided in two parts, 82134 and 5856, that added together give a triangular number (87990 = T₄₁₉).

The spelling of 821345856 in words is "eight hundred twenty-one million, three hundred forty-five thousand, eight hundred fifty-six".