1221444900 has 576 divisors, whose sum is σ = 4724697600. Its totient is φ = 267632640.

The previous prime is 1221444893. The next prime is 1221444941. The reversal of 1221444900 is 94441221.

It is a happy number.

1221444900 is a `hidden beast` number, since 1 + 2 + 214 + 449 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 13724056 + ... + 13724144.

It is an arithmetic number, because the mean of its divisors is an integer number (8202600).

Almost surely, 2^1221444900 is an apocalyptic number.

1221444900 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 1221444900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2362348800).

1221444900 is an abundant number, since it is smaller than the sum of its proper divisors (3503252700).

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

1221444900 is a wasteful number, since it uses less digits than its factorization.

1221444900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 165 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 27.

The square root of 1221444900 is about 34949.1759559507. The cubic root of 1221444900 is about 1068.9513994105.

The spelling of 1221444900 in words is "one billion, two hundred twenty-one million, four hundred forty-four thousand, nine hundred".