21645224160 has 768 divisors, whose sum is σ = 87004108800. Its totient is φ = 4409524224.

The previous prime is 21645224089. The next prime is 21645224267. The reversal of 21645224160 is 6142254612.

It is a congruent number.

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, 120922951 + ... + 120923129.

It is an arithmetic number, because the mean of its divisors is an integer number (113286600).

Almost surely, 2^21645224160 is an apocalyptic number.

21645224160 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 21645224160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43502054400).

21645224160 is an abundant number, since it is smaller than the sum of its proper divisors (65358884640).

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

21645224160 is a wasteful number, since it uses less digits than its factorization.

21645224160 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323 (or 315 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 33.

Adding to 21645224160 its reverse (6142254612), we get a palindrome (27787478772).

The spelling of 21645224160 in words is "twenty-one billion, six hundred forty-five million, two hundred twenty-four thousand, one hundred sixty".