221231031431 has 16 divisors (see below), whose sum is σ = 236485142784. Its totient is φ = 206505577344.

The previous prime is 221231031407. The next prime is 221231031433. The reversal of 221231031431 is 134130132122.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221231031431 is a prime.

It is a super-2 number, since 2×221231031431² (a number of 23 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (23).

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221231031397 and 221231031406.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221231031433) 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 15 ways as a sum of consecutive naturals, for example, 505970 + ... + 835743.

It is an arithmetic number, because the mean of its divisors is an integer number (14780321424).

Almost surely, 2^221231031431 is an apocalyptic number.

221231031431 is a deficient number, since it is larger than the sum of its proper divisors (15254111353).

221231031431 is a wasteful number, since it uses less digits than its factorization.

221231031431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1341910.

The product of its (nonzero) digits is 864, while the sum is 23.

Adding to 221231031431 its reverse (134130132122), we get a palindrome (355361163553).

The spelling of 221231031431 in words is "two hundred twenty-one billion, two hundred thirty-one million, thirty-one thousand, four hundred thirty-one".