1221440000 has 200 divisors, whose sum is σ = 3336469488. Its totient is φ = 442880000.

The previous prime is 1221439993. The next prime is 1221440053. The reversal of 1221440000 is 441221.

It is a tau number, because it is divible by the number of its divisors (200).

It is an unprimeable number.

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 19 ways as a sum of consecutive naturals, for example, 3519827 + ... + 3520173.

Almost surely, 2^1221440000 is an apocalyptic number.

1221440000 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 1221440000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1668234744).

1221440000 is an abundant number, since it is smaller than the sum of its proper divisors (2115029488).

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

1221440000 is an frugal number, since it uses more digits than its factorization.

1221440000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 396 (or 365 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 1221440000 is about 34949.1058540845. The cubic root of 1221440000 is about 1068.9499699917.

Adding to 1221440000 its reverse (441221), we get a palindrome (1221881221).

The spelling of 1221440000 in words is "one billion, two hundred twenty-one million, four hundred forty thousand".