20822561 has 4 divisors (see below), whose sum is σ = 20877312. Its totient is φ = 20767812.

The previous prime is 20822531. The next prime is 20822563. The reversal of 20822561 is 16522802.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20822561 - 2²² = 16628257 is a prime.

It is a Duffinian number.

It is a zygodrome in base 3.

It is a self number, because there is not a number n which added to its sum of digits gives 20822561.

It is not an unprimeable number, because it can be changed into a prime (20822563) 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, 26801 + ... + 27566.

It is an arithmetic number, because the mean of its divisors is an integer number (5219328).

Almost surely, 2^20822561 is an apocalyptic number.

It is an amenable number.

20822561 is a deficient number, since it is larger than the sum of its proper divisors (54751).

20822561 is an equidigital number, since it uses as much as digits as its factorization.

20822561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 54750.

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

The square root of 20822561 is about 4563.1744433015. The cubic root of 20822561 is about 275.1131699500.

The spelling of 20822561 in words is "twenty million, eight hundred twenty-two thousand, five hundred sixty-one".