21814857728 has 52 divisors (see below), whose sum is σ = 45031890048. Its totient is φ = 10555514880.

The previous prime is 21814857721. The next prime is 21814857731. The reversal of 21814857728 is 82775841812.

It is a self number, because there is not a number n which added to its sum of digits gives 21814857728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21814857721) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41075 + ... + 212877.

Almost surely, 2^21814857728 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 21814857728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22515945024).

21814857728 is an abundant number, since it is smaller than the sum of its proper divisors (23217032320).

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

21814857728 is an equidigital number, since it uses as much as digits as its factorization.

21814857728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171858 (or 171836 counting only the distinct ones).

The product of its digits is 2007040, while the sum is 53.

The spelling of 21814857728 in words is "twenty-one billion, eight hundred fourteen million, eight hundred fifty-seven thousand, seven hundred twenty-eight".