21255130512 has 320 divisors, whose sum is σ = 76628428800. Its totient is φ = 5479902720.

The previous prime is 21255130511. The next prime is 21255130517. The reversal of 21255130512 is 21503155212.

21255130512 is a `hidden beast` number, since 2 + 12 + 5 + 5 + 130 + 512 = 666.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (21255130511) 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, 4621398 + ... + 4625994.

It is an arithmetic number, because the mean of its divisors is an integer number (239463840).

Almost surely, 2^21255130512 is an apocalyptic number.

21255130512 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 21255130512, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38314214400).

21255130512 is an abundant number, since it is smaller than the sum of its proper divisors (55373298288).

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

21255130512 is a wasteful number, since it uses less digits than its factorization.

21255130512 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4771 (or 4759 counting only the distinct ones).

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

Adding to 21255130512 its reverse (21503155212), we get a palindrome (42758285724).

The spelling of 21255130512 in words is "twenty-one billion, two hundred fifty-five million, one hundred thirty thousand, five hundred twelve".