21891145752 has 512 divisors, whose sum is σ = 77104742400. Its totient is φ = 5611161600.

The previous prime is 21891145711. The next prime is 21891145753. The reversal of 21891145752 is 25754119812.

21891145752 is a `hidden beast` number, since 2 + 189 + 11 + 457 + 5 + 2 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 21891145698 and 21891145707.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21891145753) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 66136227 + ... + 66136557.

It is an arithmetic number, because the mean of its divisors is an integer number (150595200).

Almost surely, 2^21891145752 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 21891145752, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38552371200).

21891145752 is an abundant number, since it is smaller than the sum of its proper divisors (55213596648).

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

21891145752 is a wasteful number, since it uses less digits than its factorization.

21891145752 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484 (or 474 counting only the distinct ones).

The product of its digits is 201600, while the sum is 45.

The spelling of 21891145752 in words is "twenty-one billion, eight hundred ninety-one million, one hundred forty-five thousand, seven hundred fifty-two".