1821256 has 16 divisors (see below), whose sum is σ = 3432240. Its totient is φ = 906000.

The previous prime is 1821233. The next prime is 1821257. The reversal of 1821256 is 6521281.

It is a self number, because there is not a number n which added to its sum of digits gives 1821256.

It is not an unprimeable number, because it can be changed into a prime (1821257) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1555 + ... + 2461.

It is an arithmetic number, because the mean of its divisors is an integer number (214515).

2^1821256 is an apocalyptic number.

It is an amenable number.

1821256 is a deficient number, since it is larger than the sum of its proper divisors (1610984).

1821256 is a wasteful number, since it uses less digits than its factorization.

1821256 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1164 (or 1160 counting only the distinct ones).

The product of its digits is 960, while the sum is 25.

The square root of 1821256 is about 1349.5391806094. The cubic root of 1821256 is about 122.1209943591.

Adding to 1821256 its sum of digits (25), we get a palindrome (1821281).

The spelling of 1821256 in words is "one million, eight hundred twenty-one thousand, two hundred fifty-six".