11812021 has 4 divisors (see below), whose sum is σ = 12720652. Its totient is φ = 10903392.

The previous prime is 11812007. The next prime is 11812037. The reversal of 11812021 is 12021811.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12021811 = 43 ⋅279577.

It can be written as a sum of positive squares in 2 ways, for example, as 6195121 + 5616900 = 2489^2 + 2370^2 .

It is a cyclic number.

It is not a de Polignac number, because 11812021 - 2⁹ = 11811509 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11811986 and 11812004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11812621) 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 in 3 ways as a sum of consecutive naturals, for example, 454296 + ... + 454321.

It is an arithmetic number, because the mean of its divisors is an integer number (3180163).

Almost surely, 2^11812021 is an apocalyptic number.

It is an amenable number.

11812021 is a deficient number, since it is larger than the sum of its proper divisors (908631).

11812021 is an equidigital number, since it uses as much as digits as its factorization.

11812021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 908630.

The product of its (nonzero) digits is 32, while the sum is 16.

The square root of 11812021 is about 3436.8620862642. The cubic root of 11812021 is about 227.7410944869.

Adding to 11812021 its reverse (12021811), we get a palindrome (23833832).

The spelling of 11812021 in words is "eleven million, eight hundred twelve thousand, twenty-one".