1191220218 has 48 divisors (see below), whose sum is σ = 2607154056. Its totient is φ = 393068160.

The previous prime is 1191220201. The next prime is 1191220253. The reversal of 1191220218 is 8120221911.

It can be written as a sum of positive squares in 4 ways, for example, as 1048011129 + 143209089 = 32373^2 + 11967^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1191220191 and 1191220200.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 861888 + ... + 863268.

Almost surely, 2^1191220218 is an apocalyptic number.

1191220218 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

1191220218 is an abundant number, since it is smaller than the sum of its proper divisors (1415933838).

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

1191220218 is a wasteful number, since it uses less digits than its factorization.

1191220218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1839 (or 1836 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The square root of 1191220218 is about 34514.0582661616. The cubic root of 1191220218 is about 1060.0605809686.

The spelling of 1191220218 in words is "one billion, one hundred ninety-one million, two hundred twenty thousand, two hundred eighteen".