1311211220 has 48 divisors (see below), whose sum is σ = 3107462400. Its totient is φ = 460360320.

The previous prime is 1311211219. The next prime is 1311211243. The reversal of 1311211220 is 221121131.

It is a junction number, because it is equal to n+sod(n) for n = 1311211195 and 1311211204.

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, 96380 + ... + 109139.

It is an arithmetic number, because the mean of its divisors is an integer number (64738800).

Almost surely, 2^1311211220 is an apocalyptic number.

1311211220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1311211220 is an abundant number, since it is smaller than the sum of its proper divisors (1796251180).

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

1311211220 is a wasteful number, since it uses less digits than its factorization.

1311211220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 205568 (or 205566 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 14.

The square root of 1311211220 is about 36210.6506431464. The cubic root of 1311211220 is about 1094.5213033786.

Adding to 1311211220 its reverse (221121131), we get a palindrome (1532332351).

The spelling of 1311211220 in words is "one billion, three hundred eleven million, two hundred eleven thousand, two hundred twenty".