221646109 has 2 divisors, whose sum is σ = 221646110. Its totient is φ = 221646108.

The previous prime is 221646107. The next prime is 221646121. The reversal of 221646109 is 901646122.

221646109 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., 195860025 + 25786084 = 13995^2 + 5078^2 .

It is a cyclic number.

It is not a de Polignac number, because 221646109 - 2¹ = 221646107 is a prime.

Together with 221646107, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221646107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110823054 + 110823055.

It is an arithmetic number, because the mean of its divisors is an integer number (110823055).

Almost surely, 2^221646109 is an apocalyptic number.

It is an amenable number.

221646109 is a deficient number, since it is larger than the sum of its proper divisors (1).

221646109 is an equidigital number, since it uses as much as digits as its factorization.

221646109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 31.

The square root of 221646109 is about 14887.7838847829. The cubic root of 221646109 is about 605.1829776893.

The spelling of 221646109 in words is "two hundred twenty-one million, six hundred forty-six thousand, one hundred nine".