221981761 has 2 divisors, whose sum is σ = 221981762. Its totient is φ = 221981760.

The previous prime is 221981743. The next prime is 221981779. The reversal of 221981761 is 167189122.

It is a balanced prime because it is at equal distance from previous prime (221981743) and next prime (221981779).

It can be written as a sum of positive squares in only one way, i.e., 214446736 + 7535025 = 14644^2 + 2745^2 .

It is a cyclic number.

It is not a de Polignac number, because 221981761 - 2⁷ = 221981633 is a prime.

It is a super-2 number, since 2×221981761² = 98551804433322242, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 221981761.

It is not a weakly prime, because it can be changed into another prime (221981261) 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, 110990880 + 110990881.

It is an arithmetic number, because the mean of its divisors is an integer number (110990881).

Almost surely, 2^221981761 is an apocalyptic number.

It is an amenable number.

221981761 is a deficient number, since it is larger than the sum of its proper divisors (1).

221981761 is an equidigital number, since it uses as much as digits as its factorization.

221981761 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 12096, while the sum is 37.

The square root of 221981761 is about 14899.0523524149. The cubic root of 221981761 is about 605.4883119090.

The spelling of 221981761 in words is "two hundred twenty-one million, nine hundred eighty-one thousand, seven hundred sixty-one".