221613 has 16 divisors (see below), whose sum is σ = 345216. Its totient is φ = 123840.

The previous prime is 221603. The next prime is 221621. The reversal of 221613 is 316122.

It is not a de Polignac number, because 221613 - 2⁵ = 221581 is a prime.

It is a super-2 number, since 2×221613² = 98224643538, which contains 22 as substring.

It is a Curzon number.

221613 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 221592 and 221601.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221603) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1195 + ... + 1367.

It is an arithmetic number, because the mean of its divisors is an integer number (21576).

2²²¹⁶¹³ is an apocalyptic number.

It is an amenable number.

221613 is a deficient number, since it is larger than the sum of its proper divisors (123603).

221613 is a wasteful number, since it uses less digits than its factorization.

221613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 244.

The product of its digits is 72, while the sum is 15.

The square root of 221613 is about 470.7578995620. The cubic root of 221613 is about 60.5152842562.

Adding to 221613 its reverse (316122), we get a palindrome (537735).

The spelling of 221613 in words is "two hundred twenty-one thousand, six hundred thirteen".