221306399 has 2 divisors, whose sum is σ = 221306400. Its totient is φ = 221306398.

The previous prime is 221306389. The next prime is 221306417. The reversal of 221306399 is 993603122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221306399 - 2¹² = 221302303 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221306339) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110653199 + 110653200.

It is an arithmetic number, because the mean of its divisors is an integer number (110653200).

Almost surely, 2^221306399 is an apocalyptic number.

221306399 is a deficient number, since it is larger than the sum of its proper divisors (1).

221306399 is an equidigital number, since it uses as much as digits as its factorization.

221306399 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 17496, while the sum is 35.

The square root of 221306399 is about 14876.3704914875. The cubic root of 221306399 is about 604.8736379767.

The spelling of 221306399 in words is "two hundred twenty-one million, three hundred six thousand, three hundred ninety-nine".