221631131 has 2 divisors, whose sum is σ = 221631132. Its totient is φ = 221631130.

The previous prime is 221631127. The next prime is 221631247. The reversal of 221631131 is 131136122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221631131 - 2² = 221631127 is a prime.

It is a super-2 number, since 2×221631131² = 98240716456678322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (221631101) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110815565 + 110815566.

It is an arithmetic number, because the mean of its divisors is an integer number (110815566).

Almost surely, 2^221631131 is an apocalyptic number.

221631131 is a deficient number, since it is larger than the sum of its proper divisors (1).

221631131 is an equidigital number, since it uses as much as digits as its factorization.

221631131 is an evil number, because the sum of its binary digits is even.

The product of its digits is 216, while the sum is 20.

The square root of 221631131 is about 14887.2808464138. The cubic root of 221631131 is about 605.1693453952.

Adding to 221631131 its reverse (131136122), we get a palindrome (352767253).

The spelling of 221631131 in words is "two hundred twenty-one million, six hundred thirty-one thousand, one hundred thirty-one".