21266684208 has 480 divisors, whose sum is σ = 79053511680. Its totient is φ = 5166858240.

The previous prime is 21266684177. The next prime is 21266684251. The reversal of 21266684208 is 80248666212.

It is an unprimeable number.

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 95 ways as a sum of consecutive naturals, for example, 48443253 + ... + 48443691.

It is an arithmetic number, because the mean of its divisors is an integer number (164694816).

Almost surely, 2^21266684208 is an apocalyptic number.

21266684208 is a gapful number since it is divisible by the number (28) 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 21266684208, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39526755840).

21266684208 is an abundant number, since it is smaller than the sum of its proper divisors (57786827472).

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

21266684208 is a wasteful number, since it uses less digits than its factorization.

21266684208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 745 (or 736 counting only the distinct ones).

The product of its (nonzero) digits is 442368, while the sum is 45.

The spelling of 21266684208 in words is "twenty-one billion, two hundred sixty-six million, six hundred eighty-four thousand, two hundred eight".