11220821 has 2 divisors, whose sum is σ = 11220822. Its totient is φ = 11220820.

The previous prime is 11220817. The next prime is 11220841. The reversal of 11220821 is 12802211.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11122225 + 98596 = 3335^2 + 314^2 .

It is a cyclic number.

It is not a de Polignac number, because 11220821 - 2² = 11220817 is a prime.

It is a super-3 number, since 3×11220821³ (a number of 22 digits) contains 333 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 11220821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11220841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5610410 + 5610411.

It is an arithmetic number, because the mean of its divisors is an integer number (5610411).

Almost surely, 2^11220821 is an apocalyptic number.

It is an amenable number.

11220821 is a deficient number, since it is larger than the sum of its proper divisors (1).

11220821 is an equidigital number, since it uses as much as digits as its factorization.

11220821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 17.

The square root of 11220821 is about 3349.7493936114. The cubic root of 11220821 is about 223.8763467722.

The spelling of 11220821 in words is "eleven million, two hundred twenty thousand, eight hundred twenty-one".