21171880440 has 224 divisors, whose sum is σ = 71997396480. Its totient is φ = 5600399616.

The previous prime is 21171880423. The next prime is 21171880469. The reversal of 21171880440 is 4408817112.

21171880440 is a `hidden beast` number, since 21 + 17 + 188 + 0 + 440 = 666.

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 = 21171880395 and 21171880404.

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 55 ways as a sum of consecutive naturals, for example, 3700462 + ... + 3706178.

Almost surely, 2^21171880440 is an apocalyptic number.

21171880440 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 21171880440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35998698240).

21171880440 is an abundant number, since it is smaller than the sum of its proper divisors (50825516040).

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

21171880440 is a wasteful number, since it uses less digits than its factorization.

21171880440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5873 (or 5854 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The spelling of 21171880440 in words is "twenty-one billion, one hundred seventy-one million, eight hundred eighty thousand, four hundred forty".