221555461 has 2 divisors, whose sum is σ = 221555462. Its totient is φ = 221555460.

The previous prime is 221555363. The next prime is 221555473. The reversal of 221555461 is 164555122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 217120225 + 4435236 = 14735^2 + 2106^2 .

It is a cyclic number.

It is not a de Polignac number, because 221555461 - 2²³ = 213166853 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221555491) 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, 110777730 + 110777731.

It is an arithmetic number, because the mean of its divisors is an integer number (110777731).

Almost surely, 2^221555461 is an apocalyptic number.

It is an amenable number.

221555461 is a deficient number, since it is larger than the sum of its proper divisors (1).

221555461 is an equidigital number, since it uses as much as digits as its factorization.

221555461 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12000, while the sum is 31.

The square root of 221555461 is about 14884.7391982527. The cubic root of 221555461 is about 605.1004646130.

The spelling of 221555461 in words is "two hundred twenty-one million, five hundred fifty-five thousand, four hundred sixty-one".