21818363820 has 48 divisors (see below), whose sum is σ = 66645186048. Its totient is φ = 5289300160.

The previous prime is 21818363779. The next prime is 21818363821. The reversal of 21818363820 is 2836381812.

It is not an unprimeable number, because it can be changed into a prime (21818363821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 16528404 + ... + 16529723.

It is an arithmetic number, because the mean of its divisors is an integer number (1388441376).

Almost surely, 2^21818363820 is an apocalyptic number.

21818363820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21818363820 is an abundant number, since it is smaller than the sum of its proper divisors (44826822228).

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

21818363820 is a wasteful number, since it uses less digits than its factorization.

21818363820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33058150 (or 33058148 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 42.

The spelling of 21818363820 in words is "twenty-one billion, eight hundred eighteen million, three hundred sixty-three thousand, eight hundred twenty".