11115821 has 2 divisors, whose sum is σ = 11115822. Its totient is φ = 11115820.

The previous prime is 11115803. The next prime is 11115827. The reversal of 11115821 is 12851111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 10982596 + 133225 = 3314^2 + 365^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-11115821 is a prime.

It is a super-2 number, since 2×11115821² = 247122953008082, which contains 22 as substring.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 11115793 and 11115802.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11115827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5557910 + 5557911.

It is an arithmetic number, because the mean of its divisors is an integer number (5557911).

Almost surely, 2^11115821 is an apocalyptic number.

It is an amenable number.

11115821 is a deficient number, since it is larger than the sum of its proper divisors (1).

11115821 is an equidigital number, since it uses as much as digits as its factorization.

11115821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80, while the sum is 20.

The square root of 11115821 is about 3334.0397418147. The cubic root of 11115821 is about 223.1758417882.

Adding to 11115821 its reverse (12851111), we get a palindrome (23966932).

The spelling of 11115821 in words is "eleven million, one hundred fifteen thousand, eight hundred twenty-one".