821256 has 32 divisors (see below), whose sum is σ = 2162400. Its totient is φ = 259200.

The previous prime is 821209. The next prime is 821263. The reversal of 821256 is 652128.

It is a super-2 number, since 2×821256² = 1348922835072, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 445 + ... + 1356.

It is an arithmetic number, because the mean of its divisors is an integer number (67575).

2⁸²¹²⁵⁶ is an apocalyptic number.

It is an amenable number.

821256 is an abundant number, since it is smaller than the sum of its proper divisors (1341144).

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

821256 is a wasteful number, since it uses less digits than its factorization.

821256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1829 (or 1825 counting only the distinct ones).

The product of its digits is 960, while the sum is 24.

The square root of 821256 is about 906.2317584371. The cubic root of 821256 is about 93.6467806187.

The spelling of 821256 in words is "eight hundred twenty-one thousand, two hundred fifty-six".