2221981 has 2 divisors, whose sum is σ = 2221982. Its totient is φ = 2221980.

The previous prime is 2221969. The next prime is 2221991. The reversal of 2221981 is 1891222.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2088025 + 133956 = 1445^2 + 366^2 .

It is a cyclic number.

It is not a de Polignac number, because 2221981 - 2⁵ = 2221949 is a prime.

It is a super-2 number, since 2×2221981² = 9874399128722, which contains 22 as substring.

2221981 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2221931) 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, 1110990 + 1110991.

It is an arithmetic number, because the mean of its divisors is an integer number (1110991).

2^2221981 is an apocalyptic number.

It is an amenable number.

2221981 is a deficient number, since it is larger than the sum of its proper divisors (1).

2221981 is an equidigital number, since it uses as much as digits as its factorization.

2221981 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 25.

The square root of 2221981 is about 1490.6310744111. The cubic root of 2221981 is about 130.4908661027.

The spelling of 2221981 in words is "two million, two hundred twenty-one thousand, nine hundred eighty-one".