1131212220 has 48 divisors (see below), whose sum is σ = 3305111040. Its totient is φ = 288540736.

The previous prime is 1131212191. The next prime is 1131212237. The reversal of 1131212220 is 222121311.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 1131212220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 408480 + ... + 411239.

It is an arithmetic number, because the mean of its divisors is an integer number (68856480).

Almost surely, 2^1131212220 is an apocalyptic number.

1131212220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1131212220 is an abundant number, since it is smaller than the sum of its proper divisors (2173898820).

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

1131212220 is a wasteful number, since it uses less digits than its factorization.

1131212220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 819754 (or 819752 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 1131212220 is about 33633.4984799381. The cubic root of 1131212220 is about 1041.9527598459.

Adding to 1131212220 its reverse (222121311), we get a palindrome (1353333531).

Subtracting from 1131212220 its reverse (222121311), we obtain a palindrome (909090909).

It can be divided in two parts, 11312 and 12220, that added together give a palindrome (23532).

The spelling of 1131212220 in words is "one billion, one hundred thirty-one million, two hundred twelve thousand, two hundred twenty".