21055000050 has 144 divisors (see below), whose sum is σ = 66734633472. Its totient is φ = 4657305600.

The previous prime is 21055000039. The next prime is 21055000051. The reversal of 21055000050 is 5000055012.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 21054999987 and 21055000032.

It is not an unprimeable number, because it can be changed into a prime (21055000051) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 10159 + ... + 205458.

Almost surely, 2^21055000050 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21055000050, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33367316736).

21055000050 is an abundant number, since it is smaller than the sum of its proper divisors (45679633422).

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

21055000050 is a wasteful number, since it uses less digits than its factorization.

21055000050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 215673 (or 215665 counting only the distinct ones).

The product of its (nonzero) digits is 250, while the sum is 18.

Adding to 21055000050 its reverse (5000055012), we get a palindrome (26055055062).

The spelling of 21055000050 in words is "twenty-one billion, fifty-five million, fifty", and thus it is an aban number and an uban number.