1211440400 has 120 divisors (see below), whose sum is σ = 3128862240. Its totient is φ = 449095680.

The previous prime is 1211440397. The next prime is 1211440409. The reversal of 1211440400 is 40441121.

It is a super-3 number, since 3×1211440400³ (a number of 28 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is not an unprimeable number, because it can be changed into a prime (1211440409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 454271 + ... + 456929.

It is an arithmetic number, because the mean of its divisors is an integer number (26073852).

Almost surely, 2^1211440400 is an apocalyptic number.

1211440400 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 1211440400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1564431120).

1211440400 is an abundant number, since it is smaller than the sum of its proper divisors (1917421840).

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

1211440400 is a wasteful number, since it uses less digits than its factorization.

1211440400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2761 (or 2750 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

The square root of 1211440400 is about 34805.7523981310. The cubic root of 1211440400 is about 1066.0249047588.

Adding to 1211440400 its reverse (40441121), we get a palindrome (1251881521).

The spelling of 1211440400 in words is "one billion, two hundred eleven million, four hundred forty thousand, four hundred".