221549 has 2 divisors, whose sum is σ = 221550. Its totient is φ = 221548.

The previous prime is 221539. The next prime is 221567. The reversal of 221549 is 945122.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 145924 + 75625 = 382^2 + 275^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221549 is a 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 (221509) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110774 + 110775.

It is an arithmetic number, because the mean of its divisors is an integer number (110775).

2²²¹⁵⁴⁹ is an apocalyptic number.

It is an amenable number.

221549 is a deficient number, since it is larger than the sum of its proper divisors (1).

221549 is an equidigital number, since it uses as much as digits as its factorization.

221549 is an evil number, because the sum of its binary digits is even.

The product of its digits is 720, while the sum is 23.

The square root of 221549 is about 470.6899191612. The cubic root of 221549 is about 60.5094582576.

The spelling of 221549 in words is "two hundred twenty-one thousand, five hundred forty-nine".