21861265608000 has 2688 divisors, whose sum is σ = 100490257760256. Its totient is φ = 4581245952000.

The previous prime is 21861265607977. The next prime is 21861265608001. The reversal of 21861265608000 is 80656216812.

21861265608000 is a `hidden beast` number, since 2 + 1 + 8 + 6 + 1 + 2 + 6 + 560 + 80 + 0 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21861265608001) by changing a digit.

It is a polite number, since it can be written in 383 ways as a sum of consecutive naturals, for example, 33788663677 + ... + 33788664323.

It is an arithmetic number, because the mean of its divisors is an integer number (37384768512).

Almost surely, 2^{21861265608000} is an apocalyptic number.

21861265608000 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 21861265608000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50245128880128).

21861265608000 is an abundant number, since it is smaller than the sum of its proper divisors (78628992152256).

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

21861265608000 is a wasteful number, since it uses less digits than its factorization.

21861265608000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 900 (or 868 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 45.

The spelling of 21861265608000 in words is "twenty-one trillion, eight hundred sixty-one billion, two hundred sixty-five million, six hundred eight thousand".