21283758720 has 512 divisors, whose sum is σ = 86717952000. Its totient is φ = 4832759808.

The previous prime is 21283758703. The next prime is 21283758733. The reversal of 21283758720 is 2785738212.

21283758720 is a `hidden beast` number, since 2 + 12 + 8 + 37 + 587 + 20 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 21651349 + ... + 21652331.

It is an arithmetic number, because the mean of its divisors is an integer number (169371000).

Almost surely, 2^21283758720 is an apocalyptic number.

21283758720 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 21283758720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43358976000).

21283758720 is an abundant number, since it is smaller than the sum of its proper divisors (65434193280).

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

21283758720 is a wasteful number, since it uses less digits than its factorization.

21283758720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1197 (or 1179 counting only the distinct ones).

The product of its (nonzero) digits is 376320, while the sum is 45.

The spelling of 21283758720 in words is "twenty-one billion, two hundred eighty-three million, seven hundred fifty-eight thousand, seven hundred twenty".