1821313 has 8 divisors (see below), whose sum is σ = 1975400. Its totient is φ = 1679184.

The previous prime is 1821311. The next prime is 1821319. The reversal of 1821313 is 3131281.

It can be written as a sum of positive squares in 4 ways, for example, as 494209 + 1327104 = 703^2 + 1152^2 .

It is not a de Polignac number, because 1821313 - 2¹ = 1821311 is a prime.

It is a Duffinian number.

1821313 is a modest number, since divided by 1313 gives 182 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1821311) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1783 + ... + 2611.

It is an arithmetic number, because the mean of its divisors is an integer number (246925).

2^1821313 is an apocalyptic number.

1821313 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

1821313 is a deficient number, since it is larger than the sum of its proper divisors (154087).

1821313 is an frugal number, since it uses more digits than its factorization.

1821313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 868 (or 842 counting only the distinct ones).

The product of its digits is 144, while the sum is 19.

The square root of 1821313 is about 1349.5602987640. The cubic root of 1821313 is about 122.1222683561.

Adding to 1821313 its reverse (3131281), we get a palindrome (4952594).

The spelling of 1821313 in words is "one million, eight hundred twenty-one thousand, three hundred thirteen".