221145 has 16 divisors (see below), whose sum is σ = 369792. Its totient is φ = 112640.

The previous prime is 221101. The next prime is 221159. The reversal of 221145 is 541122.

It is not a de Polignac number, because 221145 - 2⁸ = 220889 is a prime.

It is a super-2 number, since 2×221145² = 97810222050, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 221145.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25 + ... + 665.

It is an arithmetic number, because the mean of its divisors is an integer number (23112).

2²²¹¹⁴⁵ is an apocalyptic number.

It is an amenable number.

221145 is a deficient number, since it is larger than the sum of its proper divisors (148647).

221145 is a wasteful number, since it uses less digits than its factorization.

221145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 672.

The product of its digits is 80, while the sum is 15.

The square root of 221145 is about 470.2605660695. The cubic root of 221145 is about 60.4726557213.

Adding to 221145 its reverse (541122), we get a palindrome (762267).

The spelling of 221145 in words is "two hundred twenty-one thousand, one hundred forty-five".