21459905280 has 864 divisors, whose sum is σ = 87241190400. Its totient is φ = 4817387520.

The previous prime is 21459905251. The next prime is 21459905287. The reversal of 21459905280 is 8250995412.

It is a happy number.

21459905280 is a `hidden beast` number, since 2 + 1 + 4 + 599 + 0 + 52 + 8 + 0 = 666.

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 (21459905287) 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, 107838621 + ... + 107838819.

It is an arithmetic number, because the mean of its divisors is an integer number (100973600).

Almost surely, 2^21459905280 is an apocalyptic number.

21459905280 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 21459905280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43620595200).

21459905280 is an abundant number, since it is smaller than the sum of its proper divisors (65781285120).

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

21459905280 is a wasteful number, since it uses less digits than its factorization.

21459905280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 297 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 21459905280 in words is "twenty-one billion, four hundred fifty-nine million, nine hundred five thousand, two hundred eighty".