21855400824960 has 192 divisors, whose sum is σ = 75487791015000. Its totient is φ = 5826689040384.

The previous prime is 21855400824949. The next prime is 21855400824989. The reversal of 21855400824960 is 6942800455812.

21855400824960 is a `hidden beast` number, since 2 + 1 + 8 + 5 + 540 + 0 + 8 + 2 + 4 + 96 + 0 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 13924778854464 + 7930621970496 = 3731592^2 + 2816136^2 .

It is a tau number, because it is divible by the number of its divisors (192).

It is a junction number, because it is equal to n+sod(n) for n = 21855400824897 and 21855400824906.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 23323566 + ... + 24242514.

Almost surely, 2^{21855400824960} is an apocalyptic number.

21855400824960 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 21855400824960, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37743895507500).

21855400824960 is an abundant number, since it is smaller than the sum of its proper divisors (53632390190040).

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

21855400824960 is a wasteful number, since it uses less digits than its factorization.

21855400824960 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 923103 (or 923088 counting only the distinct ones).

The product of its (nonzero) digits is 5529600, while the sum is 54.

The spelling of 21855400824960 in words is "twenty-one trillion, eight hundred fifty-five billion, four hundred million, eight hundred twenty-four thousand, nine hundred sixty".