221326681 has 2 divisors, whose sum is σ = 221326682. Its totient is φ = 221326680.

The previous prime is 221326657. The next prime is 221326717. The reversal of 221326681 is 186623122.

221326681 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 207821056 + 13505625 = 14416^2 + 3675^2 .

It is a cyclic number.

It is not a de Polignac number, because 221326681 - 2²¹ = 219229529 is a prime.

It is a super-2 number, since 2×221326681² = 97970999444951522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221326181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110663340 + 110663341.

It is an arithmetic number, because the mean of its divisors is an integer number (110663341).

Almost surely, 2^221326681 is an apocalyptic number.

It is an amenable number.

221326681 is a deficient number, since it is larger than the sum of its proper divisors (1).

221326681 is an equidigital number, since it uses as much as digits as its factorization.

221326681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 6912, while the sum is 31.

The square root of 221326681 is about 14877.0521609625. The cubic root of 221326681 is about 604.8921156355.

The spelling of 221326681 in words is "two hundred twenty-one million, three hundred twenty-six thousand, six hundred eighty-one".