21333996864 has 224 divisors, whose sum is σ = 67100866560. Its totient is φ = 6623133696.

The previous prime is 21333996811. The next prime is 21333996883. The reversal of 21333996864 is 46869933312.

21333996864 is a `hidden beast` number, since 2 + 133 + 399 + 68 + 64 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 21333996864.

It is a congruent number.

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 31 ways as a sum of consecutive naturals, for example, 2845729 + ... + 2853215.

It is an arithmetic number, because the mean of its divisors is an integer number (299557440).

Almost surely, 2^21333996864 is an apocalyptic number.

21333996864 is a gapful number since it is divisible by the number (24) 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 21333996864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33550433280).

21333996864 is an abundant number, since it is smaller than the sum of its proper divisors (45766869696).

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

21333996864 is a wasteful number, since it uses less digits than its factorization.

21333996864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7622 (or 7606 counting only the distinct ones).

The product of its digits is 5038848, while the sum is 54.

The spelling of 21333996864 in words is "twenty-one billion, three hundred thirty-three million, nine hundred ninety-six thousand, eight hundred sixty-four".