21144412800 has 384 divisors, whose sum is σ = 88439875200. Its totient is φ = 4832870400.

The previous prime is 21144412777. The next prime is 21144412837. The reversal of 21144412800 is 821444112.

21144412800 is a `hidden beast` number, since 211 + 4 + 441 + 2 + 8 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

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

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 47 ways as a sum of consecutive naturals, for example, 587320 + ... + 622280.

It is an arithmetic number, because the mean of its divisors is an integer number (230312175).

Almost surely, 2^21144412800 is an apocalyptic number.

21144412800 is a gapful number since it is divisible by the number (20) 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 21144412800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44219937600).

21144412800 is an abundant number, since it is smaller than the sum of its proper divisors (67295462400).

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

21144412800 is a wasteful number, since it uses less digits than its factorization.

21144412800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35001 (or 34978 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

Adding to 21144412800 its reverse (821444112), we get a palindrome (21965856912).

The spelling of 21144412800 in words is "twenty-one billion, one hundred forty-four million, four hundred twelve thousand, eight hundred".