221599 has 4 divisors (see below), whose sum is σ = 253264. Its totient is φ = 189936.

The previous prime is 221587. The next prime is 221603. The reversal of 221599 is 995122.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 995122 = 2 ⋅497561.

It is a cyclic number.

It is not a de Polignac number, because 221599 - 2⁵ = 221567 is a prime.

It is a super-2 number, since 2×221599² = 98212233602, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15822 + ... + 15835.

It is an arithmetic number, because the mean of its divisors is an integer number (63316).

2²²¹⁵⁹⁹ is an apocalyptic number.

221599 is a deficient number, since it is larger than the sum of its proper divisors (31665).

221599 is an equidigital number, since it uses as much as digits as its factorization.

221599 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31664.

The product of its digits is 1620, while the sum is 28.

The square root of 221599 is about 470.7430296882. The cubic root of 221599 is about 60.5140099149.

It can be divided in two parts, 221 and 599, that added together give a triangular number (820 = T₄₀).

The spelling of 221599 in words is "two hundred twenty-one thousand, five hundred ninety-nine".