11111220031 has 4 divisors (see below), whose sum is σ = 11114559064. Its totient is φ = 11107881000.

The previous prime is 11111220019. The next prime is 11111220037. The reversal of 11111220031 is 13002211111.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 11111220031 - 2¹⁷ = 11111088959 is a prime.

It is a super-2 number, since 2×11111220031² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 11111219993 and 11111220020.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11111220037) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1664520 + ... + 1671181.

It is an arithmetic number, because the mean of its divisors is an integer number (2778639766).

Almost surely, 2^11111220031 is an apocalyptic number.

11111220031 is a deficient number, since it is larger than the sum of its proper divisors (3339033).

11111220031 is an equidigital number, since it uses as much as digits as its factorization.

11111220031 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3339032.

The product of its (nonzero) digits is 12, while the sum is 13.

Adding to 11111220031 its reverse (13002211111), we get a palindrome (24113431142).

The spelling of 11111220031 in words is "eleven billion, one hundred eleven million, two hundred twenty thousand, thirty-one".