22056821 has 2 divisors, whose sum is σ = 22056822. Its totient is φ = 22056820.

The previous prime is 22056817. The next prime is 22056823. The reversal of 22056821 is 12865022.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 13140625 + 8916196 = 3625^2 + 2986^2 .

It is a cyclic number.

It is not a de Polignac number, because 22056821 - 2² = 22056817 is a prime.

Together with 22056823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22056823) 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, 11028410 + 11028411.

It is an arithmetic number, because the mean of its divisors is an integer number (11028411).

Almost surely, 2^22056821 is an apocalyptic number.

It is an amenable number.

22056821 is a deficient number, since it is larger than the sum of its proper divisors (1).

22056821 is an equidigital number, since it uses as much as digits as its factorization.

22056821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1920, while the sum is 26.

The square root of 22056821 is about 4696.4689927647. The cubic root of 22056821 is about 280.4449600373. Note that the first 3 decimals are identical.

The spelling of 22056821 in words is "twenty-two million, fifty-six thousand, eight hundred twenty-one".