221121281 has 2 divisors, whose sum is σ = 221121282. Its totient is φ = 221121280.

The previous prime is 221121269. The next prime is 221121293. The reversal of 221121281 is 182121122.

It is a balanced prime because it is at equal distance from previous prime (221121269) and next prime (221121293).

It can be written as a sum of positive squares in only one way, i.e., 157377025 + 63744256 = 12545^2 + 7984^2 .

It is a cyclic number.

It is not a de Polignac number, because 221121281 - 2⁶ = 221121217 is a prime.

It is a super-2 number, since 2×221121281² = 97789241822161922, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221121181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110560640 + 110560641.

It is an arithmetic number, because the mean of its divisors is an integer number (110560641).

Almost surely, 2^221121281 is an apocalyptic number.

It is an amenable number.

221121281 is a deficient number, since it is larger than the sum of its proper divisors (1).

221121281 is an equidigital number, since it uses as much as digits as its factorization.

221121281 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 128, while the sum is 20.

The square root of 221121281 is about 14870.1473092905. The cubic root of 221121281 is about 604.7049363724.

The spelling of 221121281 in words is "two hundred twenty-one million, one hundred twenty-one thousand, two hundred eighty-one".