1011221440400 has 120 divisors (see below), whose sum is σ = 2497395175080. Its totient is φ = 393197690880.

The previous prime is 1011221440351. The next prime is 1011221440403. The reversal of 1011221440400 is 40441221101.

It can be written as a sum of positive squares in 12 ways, for example, as 395429684224 + 615791756176 = 628832^2 + 784724^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (1011221440403) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 16501016 + ... + 16562184.

It is an arithmetic number, because the mean of its divisors is an integer number (20811626459).

Almost surely, 2^{1011221440400} is an apocalyptic number.

1011221440400 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 1011221440400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1248697587540).

1011221440400 is an abundant number, since it is smaller than the sum of its proper divisors (1486173734680).

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

1011221440400 is a wasteful number, since it uses less digits than its factorization.

1011221440400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62341 (or 62330 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 20.

Adding to 1011221440400 its reverse (40441221101), we get a palindrome (1051662661501).

The spelling of 1011221440400 in words is "one trillion, eleven billion, two hundred twenty-one million, four hundred forty thousand, four hundred".