1321100400 has 120 divisors (see below), whose sum is σ = 4454734720. Its totient is φ = 333745920.

The previous prime is 1321100399. The next prime is 1321100441. The reversal of 1321100400 is 40011231.

It is a happy number.

1321100400 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (120).

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6172 + ... + 51771.

Almost surely, 2^1321100400 is an apocalyptic number.

1321100400 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 1321100400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2227367360).

1321100400 is an abundant number, since it is smaller than the sum of its proper divisors (3133634320).

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

1321100400 is a wasteful number, since it uses less digits than its factorization.

1321100400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57983 (or 57972 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 1321100400 is about 36346.9448509775. The cubic root of 1321100400 is about 1097.2660481014.

Adding to 1321100400 its reverse (40011231), we get a palindrome (1361111631).

The spelling of 1321100400 in words is "one billion, three hundred twenty-one million, one hundred thousand, four hundred".