21255295684500 has 384 divisors, whose sum is σ = 73439177011200. Its totient is φ = 5296088448000.

The previous prime is 21255295684481. The next prime is 21255295684537. The reversal of 21255295684500 is 548659255212.

It is a happy number.

21255295684500 is a `hidden beast` number, since 2 + 1 + 2 + 5 + 5 + 2 + 9 + 56 + 84 + 500 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 11260824 + ... + 13012176.

It is an arithmetic number, because the mean of its divisors is an integer number (191247856800).

Almost surely, 2^{21255295684500} is an apocalyptic number.

21255295684500 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 21255295684500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36719588505600).

21255295684500 is an abundant number, since it is smaller than the sum of its proper divisors (52183881326700).

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

21255295684500 is a wasteful number, since it uses less digits than its factorization.

21255295684500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1751441 (or 1751423 counting only the distinct ones).

The product of its (nonzero) digits is 8640000, while the sum is 54.

The spelling of 21255295684500 in words is "twenty-one trillion, two hundred fifty-five billion, two hundred ninety-five million, six hundred eighty-four thousand, five hundred".