21505276938240 has 576 divisors, whose sum is σ = 78589373990400. Its totient is φ = 5423693561856.

The previous prime is 21505276938181. The next prime is 21505276938247. The reversal of 21505276938240 is 4283967250512.

21505276938240 is a `hidden beast` number, since 2 + 1 + 5 + 0 + 527 + 6 + 93 + 8 + 24 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (576).

It is not an unprimeable number, because it can be changed into a prime (21505276938247) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1062871164 + ... + 1062891396.

It is an arithmetic number, because the mean of its divisors is an integer number (136439885400).

It is a 1-persistent number, because it is pandigital, but 2⋅21505276938240 = 43010553876480 is not.

Almost surely, 2^{21505276938240} is an apocalyptic number.

21505276938240 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 21505276938240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39294686995200).

21505276938240 is an abundant number, since it is smaller than the sum of its proper divisors (57084097052160).

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

21505276938240 is a wasteful number, since it uses less digits than its factorization.

21505276938240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20892 (or 20869 counting only the distinct ones).

The product of its (nonzero) digits is 7257600, while the sum is 54.

The spelling of 21505276938240 in words is "twenty-one trillion, five hundred five billion, two hundred seventy-six million, nine hundred thirty-eight thousand, two hundred forty".