1211021118 has 24 divisors (see below), whose sum is σ = 2721060888. Its totient is φ = 403673544.

The previous prime is 1211021117. The next prime is 1211021143. The reversal of 1211021118 is 8111201121.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a self number, because there is not a number n which added to its sum of digits gives 1211021118.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1211021111) 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 11 ways as a sum of consecutive naturals, for example, 1245421 + ... + 1246392.

It is an arithmetic number, because the mean of its divisors is an integer number (113377537).

Almost surely, 2^1211021118 is an apocalyptic number.

1211021118 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1211021118 is an abundant number, since it is smaller than the sum of its proper divisors (1510039770).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1211021118 is an equidigital number, since it uses as much as digits as its factorization.

1211021118 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2491830 (or 2491818 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

The square root of 1211021118 is about 34799.7287058391. The cubic root of 1211021118 is about 1065.9019061012.

Adding to 1211021118 its reverse (8111201121), we get a palindrome (9322222239).

The spelling of 1211021118 in words is "one billion, two hundred eleven million, twenty-one thousand, one hundred eighteen".