221399 has 2 divisors, whose sum is σ = 221400. Its totient is φ = 221398.

The previous prime is 221393. The next prime is 221401. The reversal of 221399 is 993122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221399 - 2¹⁶ = 155863 is a prime.

Together with 221401, it forms a pair of twin primes.

It is a Chen prime.

It is a plaindrome in base 15.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110699 + 110700.

It is an arithmetic number, because the mean of its divisors is an integer number (110700).

2²²¹³⁹⁹ is an apocalyptic number.

221399 is a deficient number, since it is larger than the sum of its proper divisors (1).

221399 is an equidigital number, since it uses as much as digits as its factorization.

221399 is an evil number, because the sum of its binary digits is even.

The product of its digits is 972, while the sum is 26.

The square root of 221399 is about 470.5305516117. The cubic root of 221399 is about 60.4957991756.

The spelling of 221399 in words is "two hundred twenty-one thousand, three hundred ninety-nine".