21117378240 has 1792 divisors, whose sum is σ = 101125324800. Its totient is φ = 4029087744.

The previous prime is 21117378229. The next prime is 21117378283. The reversal of 21117378240 is 4287371112.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21117378195 and 21117378204.

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 255 ways as a sum of consecutive naturals, for example, 449305897 + ... + 449305943.

Almost surely, 2^21117378240 is an apocalyptic number.

21117378240 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 21117378240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (50562662400).

21117378240 is an abundant number, since it is smaller than the sum of its proper divisors (80007946560).

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

21117378240 is a wasteful number, since it uses less digits than its factorization.

21117378240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 139 (or 123 counting only the distinct ones).

The product of its (nonzero) digits is 18816, while the sum is 36.

The spelling of 21117378240 in words is "twenty-one billion, one hundred seventeen million, three hundred seventy-eight thousand, two hundred forty".