221431131 has 8 divisors (see below), whose sum is σ = 328046160. Its totient is φ = 147620736.

The previous prime is 221431127. The next prime is 221431141. The reversal of 221431131 is 131134122.

221431131 is a `hidden beast` number, since 221 + 431 + 13 + 1 = 666.

It is not a de Polignac number, because 221431131 - 2² = 221431127 is a prime.

It is a super-2 number, since 2×221431131² = 98063491551878322, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (221431141) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4100550 + ... + 4100603.

It is an arithmetic number, because the mean of its divisors is an integer number (41005770).

Almost surely, 2^221431131 is an apocalyptic number.

221431131 is a deficient number, since it is larger than the sum of its proper divisors (106615029).

221431131 is an equidigital number, since it uses as much as digits as its factorization.

221431131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8201162 (or 8201156 counting only the distinct ones).

The product of its digits is 144, while the sum is 18.

The square root of 221431131 is about 14880.5621869605. The cubic root of 221431131 is about 604.9872556111.

Adding to 221431131 its reverse (131134122), we get a palindrome (352565253).

The spelling of 221431131 in words is "two hundred twenty-one million, four hundred thirty-one thousand, one hundred thirty-one".