21281064000 has 896 divisors, whose sum is σ = 86729011200. Its totient is φ = 4490035200.

The previous prime is 21281063989. The next prime is 21281064023. The reversal of 21281064000 is 46018212.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 188327944 + ... + 188328056.

Almost surely, 2^21281064000 is an apocalyptic number.

21281064000 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 21281064000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43364505600).

21281064000 is an abundant number, since it is smaller than the sum of its proper divisors (65447947200).

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

21281064000 is a wasteful number, since it uses less digits than its factorization.

21281064000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 228 (or 208 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 24.

The spelling of 21281064000 in words is "twenty-one billion, two hundred eighty-one million, sixty-four thousand".