221539907 has 2 divisors, whose sum is σ = 221539908. Its totient is φ = 221539906.

The previous prime is 221539897. The next prime is 221539909. The reversal of 221539907 is 709935122.

221539907 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221539907 - 2⁸ = 221539651 is a prime.

Together with 221539909, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221539909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110769953 + 110769954.

It is an arithmetic number, because the mean of its divisors is an integer number (110769954).

Almost surely, 2^221539907 is an apocalyptic number.

221539907 is a deficient number, since it is larger than the sum of its proper divisors (1).

221539907 is an equidigital number, since it uses as much as digits as its factorization.

221539907 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 34020, while the sum is 38.

The square root of 221539907 is about 14884.2167076403. The cubic root of 221539907 is about 605.0863041964.

The spelling of 221539907 in words is "two hundred twenty-one million, five hundred thirty-nine thousand, nine hundred seven".