221251321 has 2 divisors, whose sum is σ = 221251322. Its totient is φ = 221251320.

The previous prime is 221251279. The next prime is 221251351. The reversal of 221251321 is 123152122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 218892025 + 2359296 = 14795^2 + 1536^2 .

It is a cyclic number.

It is not a de Polignac number, because 221251321 - 2⁷ = 221251193 is a prime.

It is not a weakly prime, because it can be changed into another prime (221251351) 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, 110625660 + 110625661.

It is an arithmetic number, because the mean of its divisors is an integer number (110625661).

Almost surely, 2^221251321 is an apocalyptic number.

It is an amenable number.

221251321 is a deficient number, since it is larger than the sum of its proper divisors (1).

221251321 is an equidigital number, since it uses as much as digits as its factorization.

221251321 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 240, while the sum is 19.

The square root of 221251321 is about 14874.5191855065. The cubic root of 221251321 is about 604.8234541673.

The spelling of 221251321 in words is "two hundred twenty-one million, two hundred fifty-one thousand, three hundred twenty-one".