221313817 has 2 divisors, whose sum is σ = 221313818. Its totient is φ = 221313816.

The previous prime is 221313793. The next prime is 221313821. The reversal of 221313817 is 718313122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 218477961 + 2835856 = 14781^2 + 1684^2 .

It is a cyclic number.

It is not a de Polignac number, because 221313817 - 2⁷ = 221313689 is a prime.

It is not a weakly prime, because it can be changed into another prime (221313847) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110656908 + 110656909.

It is an arithmetic number, because the mean of its divisors is an integer number (110656909).

Almost surely, 2^221313817 is an apocalyptic number.

It is an amenable number.

221313817 is a deficient number, since it is larger than the sum of its proper divisors (1).

221313817 is an equidigital number, since it uses as much as digits as its factorization.

221313817 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2016, while the sum is 28.

The square root of 221313817 is about 14876.6198109651. The cubic root of 221313817 is about 604.8803961824.

Adding to 221313817 its reverse (718313122), we get a palindrome (939626939).

The spelling of 221313817 in words is "two hundred twenty-one million, three hundred thirteen thousand, eight hundred seventeen".