21130005204 has 216 divisors, whose sum is σ = 68796550368. Its totient is φ = 5406065280.

The previous prime is 21130005199. The next prime is 21130005209. The reversal of 21130005204 is 40250003112.

It is an interprime number because it is at equal distance from previous prime (21130005199) and next prime (21130005209).

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21130005209) 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, 1291942 + ... + 1308194.

It is an arithmetic number, because the mean of its divisors is an integer number (318502548).

Almost surely, 2^21130005204 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 21130005204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34398275184).

21130005204 is an abundant number, since it is smaller than the sum of its proper divisors (47666545164).

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

21130005204 is a wasteful number, since it uses less digits than its factorization.

21130005204 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16355 (or 16343 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

Adding to 21130005204 its reverse (40250003112), we get a palindrome (61380008316).

The spelling of 21130005204 in words is "twenty-one billion, one hundred thirty million, five thousand, two hundred four".