1821115 has 4 divisors (see below), whose sum is σ = 2185344. Its totient is φ = 1456888.

The previous prime is 1821107. The next prime is 1821121. The reversal of 1821115 is 5111281.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1821115 - 2³ = 1821107 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 1821092 and 1821101.

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, 182107 + ... + 182116.

It is an arithmetic number, because the mean of its divisors is an integer number (546336).

2^1821115 is an apocalyptic number.

1821115 is a deficient number, since it is larger than the sum of its proper divisors (364229).

1821115 is an equidigital number, since it uses as much as digits as its factorization.

1821115 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 364228.

The product of its digits is 80, while the sum is 19.

The square root of 1821115 is about 1349.4869395441. The cubic root of 1821115 is about 122.1178427786.

Adding to 1821115 its reverse (5111281), we get a palindrome (6932396).

It can be divided in two parts, 1821 and 115, that added together give a square (1936 = 44²).

The spelling of 1821115 in words is "one million, eight hundred twenty-one thousand, one hundred fifteen".