21854543256 has 768 divisors, whose sum is σ = 82335052800. Its totient is φ = 5298628608.

The previous prime is 21854543251. The next prime is 21854543257. The reversal of 21854543256 is 65234545812.

21854543256 is a `hidden beast` number, since 2 + 1 + 8 + 54 + 543 + 2 + 56 = 666.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21854543251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 508245171 + ... + 508245213.

It is an arithmetic number, because the mean of its divisors is an integer number (107207100).

Almost surely, 2^21854543256 is an apocalyptic number.

21854543256 is a gapful number since it is divisible by the number (26) 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 21854543256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41167526400).

21854543256 is an abundant number, since it is smaller than the sum of its proper divisors (60480509544).

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

21854543256 is a wasteful number, since it uses less digits than its factorization.

21854543256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127 (or 85 counting only the distinct ones).

The product of its digits is 1152000, while the sum is 45.

The spelling of 21854543256 in words is "twenty-one billion, eight hundred fifty-four million, five hundred forty-three thousand, two hundred fifty-six".