221005439 has 2 divisors, whose sum is σ = 221005440. Its totient is φ = 221005438.

The previous prime is 221005429. The next prime is 221005441. The reversal of 221005439 is 934500122.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221005439 is a prime.

It is a Sophie Germain prime.

Together with 221005441, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221005429) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110502719 + 110502720.

It is an arithmetic number, because the mean of its divisors is an integer number (110502720).

Almost surely, 2^221005439 is an apocalyptic number.

221005439 is a deficient number, since it is larger than the sum of its proper divisors (1).

221005439 is an equidigital number, since it uses as much as digits as its factorization.

221005439 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 221005439 is about 14866.2516795593. The cubic root of 221005439 is about 604.5993194229.

The spelling of 221005439 in words is "two hundred twenty-one million, five thousand, four hundred thirty-nine".