1011221100 has 108 divisors (see below), whose sum is σ = 3255388864. Its totient is φ = 262362240.

The previous prime is 1011221083. The next prime is 1011221111. The reversal of 1011221100 is 11221101.

It is a happy number.

It is a super-2 number, since 2×1011221100² = 2045136226170420000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 18117 + ... + 48483.

Almost surely, 2^1011221100 is an apocalyptic number.

1011221100 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 1011221100, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1627694432).

1011221100 is an abundant number, since it is smaller than the sum of its proper divisors (2244167764).

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

1011221100 is a wasteful number, since it uses less digits than its factorization.

1011221100 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30424 (or 30414 counting only the distinct ones).

The product of its (nonzero) digits is 4, while the sum is 9.

The square root of 1011221100 is about 31799.7028288001. The cubic root of 1011221100 is about 1003.7264628918.

Adding to 1011221100 its reverse (11221101), we get a palindrome (1022442201).

Subtracting from 1011221100 its reverse (11221101), we obtain a palindrome (999999999).

It can be divided in two parts, 1011 and 221100, that added together give a triangular number (222111 = T₆₆₆).

The spelling of 1011221100 in words is "one billion, eleven million, two hundred twenty-one thousand, one hundred".