220312181231 has 2 divisors, whose sum is σ = 220312181232. Its totient is φ = 220312181230.

The previous prime is 220312181213. The next prime is 220312181239. The reversal of 220312181231 is 132181213022.

Together with previous prime (220312181213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-220312181231 is a prime.

It is a super-2 number, since 2×220312181231² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 220312181231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (220312181239) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110156090615 + 110156090616.

It is an arithmetic number, because the mean of its divisors is an integer number (110156090616).

Almost surely, 2^220312181231 is an apocalyptic number.

220312181231 is a deficient number, since it is larger than the sum of its proper divisors (1).

220312181231 is an equidigital number, since it uses as much as digits as its factorization.

220312181231 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 26.

Adding to 220312181231 its reverse (132181213022), we get a palindrome (352493394253).

The spelling of 220312181231 in words is "two hundred twenty billion, three hundred twelve million, one hundred eighty-one thousand, two hundred thirty-one".