21891992760 has 864 divisors, whose sum is σ = 87136620480. Its totient is φ = 4756561920.

The previous prime is 21891992719. The next prime is 21891992851. The reversal of 21891992760 is 6729919812.

21891992760 is a `hidden beast` number, since 2 + 189 + 199 + 276 + 0 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21891992697 and 21891992706.

It is a congruent number.

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 215 ways as a sum of consecutive naturals, for example, 465787057 + ... + 465787103.

It is an arithmetic number, because the mean of its divisors is an integer number (100852570).

Almost surely, 2^21891992760 is an apocalyptic number.

21891992760 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 21891992760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43568310240).

21891992760 is an abundant number, since it is smaller than the sum of its proper divisors (65244627720).

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

21891992760 is a wasteful number, since it uses less digits than its factorization.

21891992760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 157 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 54.

The spelling of 21891992760 in words is "twenty-one billion, eight hundred ninety-one million, nine hundred ninety-two thousand, seven hundred sixty".