111122222221 has 2 divisors, whose sum is σ = 111122222222. Its totient is φ = 111122222220.

The previous prime is 111122222201. The next prime is 111122222231. The reversal of 111122222221 is 122222221111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 81231270121 + 29890952100 = 285011^2 + 172890^2 .

It is an emirp because it is prime and its reverse (122222221111) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 111122222221 - 2¹³ = 111122214029 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (111122222201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55561111110 + 55561111111.

It is an arithmetic number, because the mean of its divisors is an integer number (55561111111).

Almost surely, 2^111122222221 is an apocalyptic number.

It is an amenable number.

111122222221 is a deficient number, since it is larger than the sum of its proper divisors (1).

111122222221 is an equidigital number, since it uses as much as digits as its factorization.

111122222221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 128, while the sum is 19.

Adding to 111122222221 its reverse (122222221111), we get a palindrome (233344443332).

It can be divided in two parts, 111 and 122222221, that multiplied together give a palindrome (13566666531).

The spelling of 111122222221 in words is "one hundred eleven billion, one hundred twenty-two million, two hundred twenty-two thousand, two hundred twenty-one".