1211131020 has 96 divisors (see below), whose sum is σ = 3744195840. Its totient is φ = 290056960.

The previous prime is 1211131013. The next prime is 1211131049. The reversal of 1211131020 is 201311121.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 1211130987 and 1211131005.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 43726 + ... + 65834.

It is an arithmetic number, because the mean of its divisors is an integer number (39002040).

Almost surely, 2^1211131020 is an apocalyptic number.

1211131020 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1211131020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1872097920).

1211131020 is an abundant number, since it is smaller than the sum of its proper divisors (2533064820).

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

1211131020 is a wasteful number, since it uses less digits than its factorization.

1211131020 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22215 (or 22213 counting only the distinct ones).

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

The square root of 1211131020 is about 34801.3077340493. The cubic root of 1211131020 is about 1065.9341491964.

Adding to 1211131020 its reverse (201311121), we get a palindrome (1412442141).

It can be divided in two parts, 1211 and 131020, that added together give a palindrome (132231).

The spelling of 1211131020 in words is "one billion, two hundred eleven million, one hundred thirty-one thousand, twenty".