11311331220 has 72 divisors (see below), whose sum is σ = 39212619264. Its totient is φ = 2585446848.

The previous prime is 11311331209. The next prime is 11311331221. The reversal of 11311331220 is 2213311311.

11311331220 is a `hidden beast` number, since 1 + 1 + 311 + 331 + 2 + 20 = 666.

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

It is a junction number, because it is equal to n+sod(n) for n = 11311331193 and 11311331202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (11311331221) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4487364 + ... + 4489883.

It is an arithmetic number, because the mean of its divisors is an integer number (544619712).

Almost surely, 2^11311331220 is an apocalyptic number.

11311331220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

11311331220 is an abundant number, since it is smaller than the sum of its proper divisors (27901288044).

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

11311331220 is a wasteful number, since it uses less digits than its factorization.

11311331220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8977269 (or 8977264 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 11311331220 its reverse (2213311311), we get a palindrome (13524642531).

The spelling of 11311331220 in words is "eleven billion, three hundred eleven million, three hundred thirty-one thousand, two hundred twenty".