221216131 has 4 divisors (see below), whose sum is σ = 221785200. Its totient is φ = 220647064.

The previous prime is 221216129. The next prime is 221216153. The reversal of 221216131 is 131612122.

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 221216131 - 2¹ = 221216129 is a prime.

It is a super-2 number, since 2×221216131² = 97873153229218322, 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 = 221216099 and 221216108.

It is not an unprimeable number, because it can be changed into a prime (221216431) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 283951 + ... + 284728.

It is an arithmetic number, because the mean of its divisors is an integer number (55446300).

Almost surely, 2^221216131 is an apocalyptic number.

221216131 is a deficient number, since it is larger than the sum of its proper divisors (569069).

221216131 is an equidigital number, since it uses as much as digits as its factorization.

221216131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 569068.

The product of its digits is 144, while the sum is 19.

The square root of 221216131 is about 14873.3362430895. The cubic root of 221216131 is about 604.7913867643.

Adding to 221216131 its reverse (131612122), we get a palindrome (352828253).

The spelling of 221216131 in words is "two hundred twenty-one million, two hundred sixteen thousand, one hundred thirty-one".