21816164840 has 64 divisors (see below), whose sum is σ = 50293301760. Its totient is φ = 8513105920.

The previous prime is 21816164833. The next prime is 21816164873. The reversal of 21816164840 is 4846161812.

It is a happy number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 566024 + ... + 603336.

It is an arithmetic number, because the mean of its divisors is an integer number (785832840).

Almost surely, 2^21816164840 is an apocalyptic number.

21816164840 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 21816164840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25146650880).

21816164840 is an abundant number, since it is smaller than the sum of its proper divisors (28477136920).

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

21816164840 is a wasteful number, since it uses less digits than its factorization.

21816164840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37682 (or 37678 counting only the distinct ones).

The product of its (nonzero) digits is 73728, while the sum is 41.

The spelling of 21816164840 in words is "twenty-one billion, eight hundred sixteen million, one hundred sixty-four thousand, eight hundred forty".