21605225025500 has 96 divisors (see below), whose sum is σ = 48837713520960. Its totient is φ = 8339846726400.

The previous prime is 21605225025443. The next prime is 21605225025509. The reversal of 21605225025500 is 552052250612.

It is a super-3 number, since 3×21605225025500³ (a number of 41 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21605225025509) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 28230899 + ... + 28986101.

It is an arithmetic number, because the mean of its divisors is an integer number (508726182510).

Almost surely, 2^{21605225025500} is an apocalyptic number.

21605225025500 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 21605225025500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24418856760480).

21605225025500 is an abundant number, since it is smaller than the sum of its proper divisors (27232488495460).

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

21605225025500 is a wasteful number, since it uses less digits than its factorization.

21605225025500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 757224 (or 757212 counting only the distinct ones).

The product of its (nonzero) digits is 60000, while the sum is 35.

The spelling of 21605225025500 in words is "twenty-one trillion, six hundred five billion, two hundred twenty-five million, twenty-five thousand, five hundred".