21531054240400 has 120 divisors (see below), whose sum is σ = 53103512970144. Its totient is φ = 8384367436800.

The previous prime is 21531054240379. The next prime is 21531054240529. The reversal of 21531054240400 is 404245013512.

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, 6253159 + ... + 9064441.

Almost surely, 2^{21531054240400} is an apocalyptic number.

21531054240400 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 21531054240400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26551756485072).

21531054240400 is an abundant number, since it is smaller than the sum of its proper divisors (31572458729744).

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

21531054240400 is a wasteful number, since it uses less digits than its factorization.

21531054240400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2811809 (or 2811798 counting only the distinct ones).

The product of its (nonzero) digits is 19200, while the sum is 31.

Adding to 21531054240400 its reverse (404245013512), we get a palindrome (21935299253912).

The spelling of 21531054240400 in words is "twenty-one trillion, five hundred thirty-one billion, fifty-four million, two hundred forty thousand, four hundred".