1211108220 has 384 divisors, whose sum is σ = 4668088320. Its totient is φ = 254361600.

The previous prime is 1211108219. The next prime is 1211108257. The reversal of 1211108220 is 228011121.

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 = 1211108193 and 1211108202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 3020020 + ... + 3020420.

It is an arithmetic number, because the mean of its divisors is an integer number (12156480).

Almost surely, 2^1211108220 is an apocalyptic number.

1211108220 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 1211108220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2334044160).

1211108220 is an abundant number, since it is smaller than the sum of its proper divisors (3456980100).

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

1211108220 is a wasteful number, since it uses less digits than its factorization.

1211108220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 490 (or 482 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 1211108220 is about 34800.9801586105. The cubic root of 1211108220 is about 1065.9274602831.

Adding to 1211108220 its reverse (228011121), we get a palindrome (1439119341).

The spelling of 1211108220 in words is "one billion, two hundred eleven million, one hundred eight thousand, two hundred twenty".