12565423728 has 200 divisors, whose sum is σ = 42726650736. Its totient is φ = 3514752000.

The previous prime is 12565423721. The next prime is 12565423799. The reversal of 12565423728 is 82732456521.

12565423728 is a `hidden beast` number, since 1 + 2 + 56 + 542 + 37 + 28 = 666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12565423721) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 151428 + ... + 219228.

Almost surely, 2^12565423728 is an apocalyptic number.

12565423728 is a gapful number since it is divisible by the number (18) 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 12565423728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21363325368).

12565423728 is an abundant number, since it is smaller than the sum of its proper divisors (30161227008).

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

12565423728 is a wasteful number, since it uses less digits than its factorization.

12565423728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 67845 (or 67830 counting only the distinct ones).

The product of its digits is 806400, while the sum is 45.

The spelling of 12565423728 in words is "twelve billion, five hundred sixty-five million, four hundred twenty-three thousand, seven hundred twenty-eight".