520001221 has 2 divisors, whose sum is σ = 520001222. Its totient is φ = 520001220.

The previous prime is 520001213. The next prime is 520001249. The reversal of 520001221 is 122100025.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 485320900 + 34680321 = 22030^2 + 5889^2 .

It is a cyclic number.

It is not a de Polignac number, because 520001221 - 2³ = 520001213 is a prime.

520001221 is a modest number, since divided by 1221 gives 520 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (520001201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 260000610 + 260000611.

It is an arithmetic number, because the mean of its divisors is an integer number (260000611).

Almost surely, 2^520001221 is an apocalyptic number.

It is an amenable number.

520001221 is a deficient number, since it is larger than the sum of its proper divisors (1).

520001221 is an equidigital number, since it uses as much as digits as its factorization.

520001221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40, while the sum is 13.

The square root of 520001221 is about 22803.5352741631. The cubic root of 520001221 is about 804.1457811155.

Adding to 520001221 its reverse (122100025), we get a palindrome (642101246).

The spelling of 520001221 in words is "five hundred twenty million, one thousand, two hundred twenty-one".