1313821 has 4 divisors (see below), whose sum is σ = 1316700. Its totient is φ = 1310944.

The previous prime is 1313813. The next prime is 1313827. The reversal of 1313821 is 1283131.

1313821 = 810² + 811².

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1283131 = 233 ⋅5507.

It can be written as a sum of positive squares in 2 ways, for example, as 656100 + 657721 = 810^2 + 811^2 .

It is a cyclic number.

It is not a de Polignac number, because 1313821 - 2³ = 1313813 is a prime.

It is a super-2 number, since 2×1313821² = 3452251240082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1313827) 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, 586 + ... + 1723.

It is an arithmetic number, because the mean of its divisors is an integer number (329175).

2^1313821 is an apocalyptic number.

1313821 is the 811-st centered square number.

It is an amenable number.

1313821 is a deficient number, since it is larger than the sum of its proper divisors (2879).

1313821 is an equidigital number, since it uses as much as digits as its factorization.

1313821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2878.

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

The square root of 1313821 is about 1146.2203104116. The cubic root of 1313821 is about 109.5246985285.

Adding to 1313821 its reverse (1283131), we get a palindrome (2596952).

The spelling of 1313821 in words is "one million, three hundred thirteen thousand, eight hundred twenty-one".