21131054250 has 128 divisors (see below), whose sum is σ = 55641980160. Its totient is φ = 5326560000.

The previous prime is 21131054239. The next prime is 21131054297. The reversal of 21131054250 is 5245013112.

It is a happy number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 21131054250.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 7707880 + ... + 7710620.

It is an arithmetic number, because the mean of its divisors is an integer number (434702970).

Almost surely, 2^21131054250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21131054250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27820990080).

21131054250 is an abundant number, since it is smaller than the sum of its proper divisors (34510925910).

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

21131054250 is a wasteful number, since it uses less digits than its factorization.

21131054250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3321 (or 3311 counting only the distinct ones).

The product of its (nonzero) digits is 1200, while the sum is 24.

Adding to 21131054250 its reverse (5245013112), we get a palindrome (26376067362).

The spelling of 21131054250 in words is "twenty-one billion, one hundred thirty-one million, fifty-four thousand, two hundred fifty".