1821320 has 16 divisors (see below), whose sum is σ = 4098060. Its totient is φ = 728512.

The previous prime is 1821319. The next prime is 1821331. The reversal of 1821320 is 231281.

It can be written as a sum of positive squares in 2 ways, for example, as 1811716 + 9604 = 1346^2 + 98^2 .

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, 22727 + ... + 22806.

2^1821320 is an apocalyptic number.

1821320 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1821320 is an abundant number, since it is smaller than the sum of its proper divisors (2276740).

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

1821320 is a wasteful number, since it uses less digits than its factorization.

1821320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45544 (or 45540 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 1821320 is about 1349.5628921988. The cubic root of 1821320 is about 122.1224248100.

The spelling of 1821320 in words is "one million, eight hundred twenty-one thousand, three hundred twenty".