21337903872 has 216 divisors, whose sum is σ = 67557396816. Its totient is φ = 6693912576.

The previous prime is 21337903831. The next prime is 21337903891. The reversal of 21337903872 is 27830973312.

It is a tau number, because it is divible by the number of its divisors (216).

It is a super-2 number, since 2×21337903872² (a number of 21 digits) contains 22 as substring.

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 23 ways as a sum of consecutive naturals, for example, 1047448 + ... + 1067624.

It is an arithmetic number, because the mean of its divisors is an integer number (312765726).

Almost surely, 2^21337903872 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21337903872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33778698408).

21337903872 is an abundant number, since it is smaller than the sum of its proper divisors (46219492944).

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

21337903872 is an equidigital number, since it uses as much as digits as its factorization.

21337903872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20225 (or 20199 counting only the distinct ones).

The product of its (nonzero) digits is 381024, while the sum is 45.

The spelling of 21337903872 in words is "twenty-one billion, three hundred thirty-seven million, nine hundred three thousand, eight hundred seventy-two".