1311821 has 8 divisors (see below), whose sum is σ = 1508544. Its totient is φ = 1117440.

The previous prime is 1311799. The next prime is 1311829. The reversal of 1311821 is 1281131.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1311821 - 2¹⁰ = 1310797 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1311821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1311829) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 866 + ... + 1836.

It is an arithmetic number, because the mean of its divisors is an integer number (188568).

2^1311821 is an apocalyptic number.

It is an amenable number.

1311821 is a deficient number, since it is larger than the sum of its proper divisors (196723).

1311821 is an equidigital number, since it uses as much as digits as its factorization.

1311821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1171.

The product of its digits is 48, while the sum is 17.

The square root of 1311821 is about 1145.3475455075. The cubic root of 1311821 is about 109.4690946468.

Adding to 1311821 its reverse (1281131), we get a palindrome (2592952).

The spelling of 1311821 in words is "one million, three hundred eleven thousand, eight hundred twenty-one".