20822821 has 2 divisors, whose sum is σ = 20822822. Its totient is φ = 20822820.

The previous prime is 20822717. The next prime is 20822831. The reversal of 20822821 is 12822802.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20205025 + 617796 = 4495^2 + 786^2 .

It is a cyclic number.

It is not a de Polignac number, because 20822821 - 2²¹ = 18725669 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20822831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10411410 + 10411411.

It is an arithmetic number, because the mean of its divisors is an integer number (10411411).

Almost surely, 2^20822821 is an apocalyptic number.

It is an amenable number.

20822821 is a deficient number, since it is larger than the sum of its proper divisors (1).

20822821 is an equidigital number, since it uses as much as digits as its factorization.

20822821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1024, while the sum is 25.

The square root of 20822821 is about 4563.2029321519. The cubic root of 20822821 is about 275.1143150081.

The spelling of 20822821 in words is "twenty million, eight hundred twenty-two thousand, eight hundred twenty-one".