21155235104 has 96 divisors (see below), whose sum is σ = 43225902720. Its totient is φ = 10185062400.

The previous prime is 21155235103. The next prime is 21155235121. The reversal of 21155235104 is 40153255112.

It is not an unprimeable number, because it can be changed into a prime (21155235103) 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, 56716262 + ... + 56716634.

It is an arithmetic number, because the mean of its divisors is an integer number (450269820).

Almost surely, 2^21155235104 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 21155235104, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21612951360).

21155235104 is an abundant number, since it is smaller than the sum of its proper divisors (22070667616).

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

21155235104 is a wasteful number, since it uses less digits than its factorization.

21155235104 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 874 (or 866 counting only the distinct ones).

The product of its (nonzero) digits is 6000, while the sum is 29.

The spelling of 21155235104 in words is "twenty-one billion, one hundred fifty-five million, two hundred thirty-five thousand, one hundred four".