220810021 has 2 divisors, whose sum is σ = 220810022. Its totient is φ = 220810020.

The previous prime is 220810013. The next prime is 220810033. The reversal of 220810021 is 120018022.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 152152225 + 68657796 = 12335^2 + 8286^2 .

It is a cyclic number.

It is not a de Polignac number, because 220810021 - 2³ = 220810013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 220809977 and 220810004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220814021) 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, 110405010 + 110405011.

It is an arithmetic number, because the mean of its divisors is an integer number (110405011).

Almost surely, 2^220810021 is an apocalyptic number.

It is an amenable number.

220810021 is a deficient number, since it is larger than the sum of its proper divisors (1).

220810021 is an equidigital number, since it uses as much as digits as its factorization.

220810021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 16.

The square root of 220810021 is about 14859.6776882946. The cubic root of 220810021 is about 604.4210667504.

Adding to 220810021 its reverse (120018022), we get a palindrome (340828043).

The spelling of 220810021 in words is "two hundred twenty million, eight hundred ten thousand, twenty-one".