21338871840 has 576 divisors, whose sum is σ = 86187628800. Its totient is φ = 4739604480.

The previous prime is 21338871833. The next prime is 21338871857. The reversal of 21338871840 is 4817883312.

21338871840 is a `hidden beast` number, since 213 + 388 + 7 + 18 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

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 95 ways as a sum of consecutive naturals, for example, 35623861 + ... + 35624459.

It is an arithmetic number, because the mean of its divisors is an integer number (149631300).

Almost surely, 2^21338871840 is an apocalyptic number.

21338871840 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 21338871840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43093814400).

21338871840 is an abundant number, since it is smaller than the sum of its proper divisors (64848756960).

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

21338871840 is a wasteful number, since it uses less digits than its factorization.

21338871840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 817 (or 806 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 45.

The spelling of 21338871840 in words is "twenty-one billion, three hundred thirty-eight million, eight hundred seventy-one thousand, eight hundred forty".