21861633024 has 792 divisors, whose sum is σ = 83583235008. Its totient is φ = 5643509760.

The previous prime is 21861633023. The next prime is 21861633029. The reversal of 21861633024 is 42033616812.

21861633024 is a `hidden beast` number, since 2 + 1 + 8 + 616 + 3 + 30 + 2 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (792).

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

It is a self number, because there is not a number n which added to its sum of digits gives 21861633024.

It is not an unprimeable number, because it can be changed into a prime (21861633023) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 134120367 + ... + 134120529.

Almost surely, 2^21861633024 is an apocalyptic number.

21861633024 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 21861633024, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41791617504).

21861633024 is an abundant number, since it is smaller than the sum of its proper divisors (61721601984).

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

21861633024 is a wasteful number, since it uses less digits than its factorization.

21861633024 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223 (or 186 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 36.

The spelling of 21861633024 in words is "twenty-one billion, eight hundred sixty-one million, six hundred thirty-three thousand, twenty-four".