21155455112 has 96 divisors (see below), whose sum is σ = 46287271800. Its totient is φ = 9026519040.

The previous prime is 21155455081. The next prime is 21155455157.

21155455112 is nontrivially palindromic in base 10.

It can be written as a sum of positive squares in 4 ways, for example, as 9831515716 + 11323939396 = 99154^2 + 106414^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7123964 + ... + 7126932.

Almost surely, 2^21155455112 is an apocalyptic number.

21155455112 is a gapful number since it is divisible by the number (22) 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 21155455112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23143635900).

21155455112 is an abundant number, since it is smaller than the sum of its proper divisors (25131816688).

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

21155455112 is a wasteful number, since it uses less digits than its factorization.

21155455112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3447 (or 3432 counting only the distinct ones).

The product of its digits is 10000, while the sum is 32.

The spelling of 21155455112 in words is "twenty-one billion, one hundred fifty-five million, four hundred fifty-five thousand, one hundred twelve".