21280454250 has 128 divisors (see below), whose sum is σ = 58488708096. Its totient is φ = 5110472000.

The previous prime is 21280454249. The next prime is 21280454257. The reversal of 21280454250 is 5245408212.

It is a Harshad number since it is a multiple of its sum of digits (33).

It is not an unprimeable number, because it can be changed into a prime (21280454257) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 870697 + ... + 894803.

It is an arithmetic number, because the mean of its divisors is an integer number (456943032).

Almost surely, 2^21280454250 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21280454250, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29244354048).

21280454250 is an abundant number, since it is smaller than the sum of its proper divisors (37208253846).

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

21280454250 is a wasteful number, since it uses less digits than its factorization.

21280454250 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24245 (or 24235 counting only the distinct ones).

The product of its (nonzero) digits is 25600, while the sum is 33.

The spelling of 21280454250 in words is "twenty-one billion, two hundred eighty million, four hundred fifty-four thousand, two hundred fifty".