20504221 has 2 divisors, whose sum is σ = 20504222. Its totient is φ = 20504220.

The previous prime is 20504203. The next prime is 20504353. The reversal of 20504221 is 12240502.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12602500 + 7901721 = 3550^2 + 2811^2 .

It is a cyclic number.

It is not a de Polignac number, because 20504221 - 2⁹ = 20503709 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20504195 and 20504204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20504921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10252110 + 10252111.

It is an arithmetic number, because the mean of its divisors is an integer number (10252111).

Almost surely, 2^20504221 is an apocalyptic number.

It is an amenable number.

20504221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20504221 is an equidigital number, since it uses as much as digits as its factorization.

20504221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 160, while the sum is 16.

The square root of 20504221 is about 4528.1586765483. The cubic root of 20504221 is about 273.7039665998.

Adding to 20504221 its reverse (12240502), we get a palindrome (32744723).

The spelling of 20504221 in words is "twenty million, five hundred four thousand, two hundred twenty-one".