1820864 has 28 divisors (see below), whose sum is σ = 3773424. Its totient is φ = 870144.

The previous prime is 1820857. The next prime is 1820869. The reversal of 1820864 is 4680281.

It is not an unprimeable number, because it can be changed into a prime (1820869) 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, 854 + ... + 2090.

2^1820864 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 1820864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1886712).

1820864 is an abundant number, since it is smaller than the sum of its proper divisors (1952560).

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

1820864 is a wasteful number, since it uses less digits than its factorization.

1820864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1272 (or 1262 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 1820864 is about 1349.3939380329. The cubic root of 1820864 is about 122.1122321158.

The spelling of 1820864 in words is "one million, eight hundred twenty thousand, eight hundred sixty-four".