1221544472400 has 1440 divisors, whose sum is σ = 5388340838400. Its totient is φ = 249838387200.

The previous prime is 1221544472347. The next prime is 1221544472413. The reversal of 1221544472400 is 42744451221.

1221544472400 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 544 + 4 + 72 + 40 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 287 ways as a sum of consecutive naturals, for example, 783542821 + ... + 783544379.

It is an arithmetic number, because the mean of its divisors is an integer number (3741903360).

Almost surely, 2^{1221544472400} is an apocalyptic number.

1221544472400 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 1221544472400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2694170419200).

1221544472400 is an abundant number, since it is smaller than the sum of its proper divisors (4166796366000).

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

1221544472400 is a wasteful number, since it uses less digits than its factorization.

1221544472400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1697 (or 1683 counting only the distinct ones).

The product of its (nonzero) digits is 71680, while the sum is 36.

The spelling of 1221544472400 in words is "one trillion, two hundred twenty-one billion, five hundred forty-four million, four hundred seventy-two thousand, four hundred".