21285089280 has 1248 divisors, whose sum is σ = 96172038144. Its totient is φ = 4395368448.

The previous prime is 21285089261. The next prime is 21285089281. The reversal of 21285089280 is 8298058212.

21285089280 is a `hidden beast` number, since 212 + 85 + 0 + 89 + 280 = 666.

It is a tau number, because it is divible by the number of its divisors (1248).

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

It is not an unprimeable number, because it can be changed into a prime (21285089281) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 452874217 + ... + 452874263.

It is an arithmetic number, because the mean of its divisors is an integer number (77060928).

Almost surely, 2^21285089280 is an apocalyptic number.

21285089280 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 21285089280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48086019072).

21285089280 is an abundant number, since it is smaller than the sum of its proper divisors (74886948864).

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

21285089280 is an equidigital number, since it uses as much as digits as its factorization.

21285089280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 184320, while the sum is 45.

The spelling of 21285089280 in words is "twenty-one billion, two hundred eighty-five million, eighty-nine thousand, two hundred eighty".