21251515230 has 192 divisors, whose sum is σ = 63063748800. Its totient is φ = 4917749760.

The previous prime is 21251515223. The next prime is 21251515237. The reversal of 21251515230 is 3251515212.

21251515230 is a `hidden beast` number, since 2 + 125 + 1 + 515 + 23 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (21251515223) and next prime (21251515237).

It is a junction number, because it is equal to n+sod(n) for n = 21251515194 and 21251515203.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251515237) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 2551032 + ... + 2559348.

It is an arithmetic number, because the mean of its divisors is an integer number (328457025).

Almost surely, 2^21251515230 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21251515230, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31531874400).

21251515230 is an abundant number, since it is smaller than the sum of its proper divisors (41812233570).

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

21251515230 is a wasteful number, since it uses less digits than its factorization.

21251515230 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8459 (or 8456 counting only the distinct ones).

The product of its (nonzero) digits is 3000, while the sum is 27.

The spelling of 21251515230 in words is "twenty-one billion, two hundred fifty-one million, five hundred fifteen thousand, two hundred thirty".