221220257 has 2 divisors, whose sum is σ = 221220258. Its totient is φ = 221220256.

The previous prime is 221220229. The next prime is 221220283. The reversal of 221220257 is 752022122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 172764736 + 48455521 = 13144^2 + 6961^2 .

It is a cyclic number.

It is not a de Polignac number, because 221220257 - 2¹⁰ = 221219233 is a prime.

It is not a weakly prime, because it can be changed into another prime (221220457) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610128 + 110610129.

It is an arithmetic number, because the mean of its divisors is an integer number (110610129).

Almost surely, 2^221220257 is an apocalyptic number.

It is an amenable number.

221220257 is a deficient number, since it is larger than the sum of its proper divisors (1).

221220257 is an equidigital number, since it uses as much as digits as its factorization.

221220257 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1120, while the sum is 23.

The square root of 221220257 is about 14873.4749470324. The cubic root of 221220257 is about 604.7951468182.

Adding to 221220257 its reverse (752022122), we get a palindrome (973242379).

The spelling of 221220257 in words is "two hundred twenty-one million, two hundred twenty thousand, two hundred fifty-seven".