21798125568 has 272 divisors, whose sum is σ = 65766184960. Its totient is φ = 7134511104.

The previous prime is 21798125567. The next prime is 21798125597. The reversal of 21798125568 is 86552189712.

21798125568 is a `hidden beast` number, since 2 + 1 + 7 + 9 + 81 + 2 + 556 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21798125567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 171638721 + ... + 171638847.

Almost surely, 2^21798125568 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 21798125568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32883092480).

21798125568 is an abundant number, since it is smaller than the sum of its proper divisors (43968059392).

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

21798125568 is an frugal number, since it uses more digits than its factorization.

21798125568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 265 (or 229 counting only the distinct ones).

The product of its digits is 2419200, while the sum is 54.

The spelling of 21798125568 in words is "twenty-one billion, seven hundred ninety-eight million, one hundred twenty-five thousand, five hundred sixty-eight".