221944861 has 2 divisors, whose sum is σ = 221944862. Its totient is φ = 221944860.

The previous prime is 221944829. The next prime is 221944883. The reversal of 221944861 is 168449122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 141752836 + 80192025 = 11906^2 + 8955^2 .

It is a cyclic number.

It is not a de Polignac number, because 221944861 - 2⁵ = 221944829 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221944861.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221944361) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110972430 + 110972431.

It is an arithmetic number, because the mean of its divisors is an integer number (110972431).

Almost surely, 2^221944861 is an apocalyptic number.

It is an amenable number.

221944861 is a deficient number, since it is larger than the sum of its proper divisors (1).

221944861 is an equidigital number, since it uses as much as digits as its factorization.

221944861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 37.

The square root of 221944861 is about 14897.8139671564. The cubic root of 221944861 is about 605.4547599681.

The spelling of 221944861 in words is "two hundred twenty-one million, nine hundred forty-four thousand, eight hundred sixty-one".