21198378755872 has 96 divisors (see below), whose sum is σ = 42996245160960. Its totient is φ = 10281816760320.

The previous prime is 21198378755843. The next prime is 21198378755923. The reversal of 21198378755872 is 27855787389112.

It is a junction number, because it is equal to n+sod(n) for n = 21198378755795 and 21198378755804.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 162201529 + ... + 162332167.

It is an arithmetic number, because the mean of its divisors is an integer number (447877553760).

Almost surely, 2^{21198378755872} 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 21198378755872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21498122580480).

21198378755872 is an abundant number, since it is smaller than the sum of its proper divisors (21797866405088).

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

21198378755872 is a wasteful number, since it uses less digits than its factorization.

21198378755872 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 131394 (or 131386 counting only the distinct ones).

The product of its digits is 474163200, while the sum is 73.

The spelling of 21198378755872 in words is "twenty-one trillion, one hundred ninety-eight billion, three hundred seventy-eight million, seven hundred fifty-five thousand, eight hundred seventy-two".