21853218660 has 192 divisors, whose sum is σ = 75510489600. Its totient is φ = 4598489088.

The previous prime is 21853218577. The next prime is 21853218671. The reversal of 21853218660 is 6681235812.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 2118796 + ... + 2129084.

It is an arithmetic number, because the mean of its divisors is an integer number (393283800).

Almost surely, 2^21853218660 is an apocalyptic number.

21853218660 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 21853218660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37755244800).

21853218660 is an abundant number, since it is smaller than the sum of its proper divisors (53657270940).

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

21853218660 is a wasteful number, since it uses less digits than its factorization.

21853218660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10710 (or 10708 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 42.

The spelling of 21853218660 in words is "twenty-one billion, eight hundred fifty-three million, two hundred eighteen thousand, six hundred sixty".