21457843881984 has 336 divisors, whose sum is σ = 64652541408000. Its totient is φ = 7116573302784.

The previous prime is 21457843881979. The next prime is 21457843882031. The reversal of 21457843881984 is 48918834875412.

21457843881984 is a `hidden beast` number, since 2 + 1 + 4 + 57 + 8 + 4 + 388 + 198 + 4 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

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 27 ways as a sum of consecutive naturals, for example, 297069297 + ... + 297141519.

It is an arithmetic number, because the mean of its divisors is an integer number (192418278000).

Almost surely, 2^{21457843881984} is an apocalyptic number.

21457843881984 is a gapful number since it is divisible by the number (24) 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 21457843881984, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32326270704000).

21457843881984 is an abundant number, since it is smaller than the sum of its proper divisors (43194697526016).

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

21457843881984 is an frugal number, since it uses more digits than its factorization.

21457843881984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72462 (or 72427 counting only the distinct ones).

The product of its digits is 495452160, while the sum is 72.

The spelling of 21457843881984 in words is "twenty-one trillion, four hundred fifty-seven billion, eight hundred forty-three million, eight hundred eighty-one thousand, nine hundred eighty-four".