22809821 has 2 divisors, whose sum is σ = 22809822. Its totient is φ = 22809820.

The previous prime is 22809781. The next prime is 22809827. The reversal of 22809821 is 12890822.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 22372900 + 436921 = 4730^2 + 661^2 .

It is a cyclic number.

It is not a de Polignac number, because 22809821 - 2¹⁸ = 22547677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22809827) 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, 11404910 + 11404911.

It is an arithmetic number, because the mean of its divisors is an integer number (11404911).

Almost surely, 2^22809821 is an apocalyptic number.

It is an amenable number.

22809821 is a deficient number, since it is larger than the sum of its proper divisors (1).

22809821 is an equidigital number, since it uses as much as digits as its factorization.

22809821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 22809821 is about 4775.9628348638. The cubic root of 22809821 is about 283.6006960328.

The spelling of 22809821 in words is "twenty-two million, eight hundred nine thousand, eight hundred twenty-one".