21265382880 has 288 divisors, whose sum is σ = 83157617088. Its totient is φ = 4847616000.

The previous prime is 21265382869. The next prime is 21265382903. The reversal of 21265382880 is 8828356212.

21265382880 is a `hidden beast` number, since 2 + 1 + 265 + 382 + 8 + 8 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4039450 + ... + 4044710.

It is an arithmetic number, because the mean of its divisors is an integer number (288741726).

Almost surely, 2^21265382880 is an apocalyptic number.

21265382880 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 21265382880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41578808544).

21265382880 is an abundant number, since it is smaller than the sum of its proper divisors (61892234208).

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

21265382880 is a wasteful number, since it uses less digits than its factorization.

21265382880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5690 (or 5679 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The spelling of 21265382880 in words is "twenty-one billion, two hundred sixty-five million, three hundred eighty-two thousand, eight hundred eighty".