221513123 has 4 divisors (see below), whose sum is σ = 238552608. Its totient is φ = 204473640.

The previous prime is 221513093. The next prime is 221513147. The reversal of 221513123 is 321315122.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 221513123 - 2¹⁰ = 221512099 is a prime.

It is a super-2 number, since 2×221513123² = 98136127322426258, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221513095 and 221513104.

It is not an unprimeable number, because it can be changed into a prime (221513623) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8519723 + ... + 8519748.

It is an arithmetic number, because the mean of its divisors is an integer number (59638152).

Almost surely, 2^221513123 is an apocalyptic number.

221513123 is a deficient number, since it is larger than the sum of its proper divisors (17039485).

221513123 is a wasteful number, since it uses less digits than its factorization.

221513123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17039484.

The product of its digits is 360, while the sum is 20.

The square root of 221513123 is about 14883.3169354146. The cubic root of 221513123 is about 605.0619183947.

Adding to 221513123 its reverse (321315122), we get a palindrome (542828245).

The spelling of 221513123 in words is "two hundred twenty-one million, five hundred thirteen thousand, one hundred twenty-three".