21647223360 has 672 divisors, whose sum is σ = 91305107712. Its totient is φ = 4594728960.

The previous prime is 21647223359. The next prime is 21647223373. The reversal of 21647223360 is 6332274612.

21647223360 is a `hidden beast` number, since 2 + 1 + 647 + 2 + 2 + 3 + 3 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 28445380 + ... + 28446140.

It is an arithmetic number, because the mean of its divisors is an integer number (135870696).

Almost surely, 2^21647223360 is an apocalyptic number.

21647223360 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 21647223360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45652553856).

21647223360 is an abundant number, since it is smaller than the sum of its proper divisors (69657884352).

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

21647223360 is a wasteful number, since it uses less digits than its factorization.

21647223360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 891 (or 878 counting only the distinct ones).

The product of its (nonzero) digits is 72576, while the sum is 36.

Adding to 21647223360 its reverse (6332274612), we get a palindrome (27979497972).

The spelling of 21647223360 in words is "twenty-one billion, six hundred forty-seven million, two hundred twenty-three thousand, three hundred sixty".