21130345852 has 72 divisors (see below), whose sum is σ = 47295940608. Its totient is φ = 8167672800.

The previous prime is 21130345807. The next prime is 21130345861. The reversal of 21130345852 is 25854303112.

It is a congruent number.

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, 235227 + ... + 312397.

It is an arithmetic number, because the mean of its divisors is an integer number (656888064).

Almost surely, 2^21130345852 is an apocalyptic number.

21130345852 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 21130345852, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23647970304).

21130345852 is an abundant number, since it is smaller than the sum of its proper divisors (26165594756).

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

21130345852 is a wasteful number, since it uses less digits than its factorization.

21130345852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 77327 (or 77318 counting only the distinct ones).

The product of its (nonzero) digits is 28800, while the sum is 34.

Adding to 21130345852 its reverse (25854303112), we get a palindrome (46984648964).

The spelling of 21130345852 in words is "twenty-one billion, one hundred thirty million, three hundred forty-five thousand, eight hundred fifty-two".