12561388533 has 12 divisors (see below), whose sum is σ = 18348096780. Its totient is φ = 8280165696.

The previous prime is 12561388531. The next prime is 12561388561. The reversal of 12561388533 is 33588316521.

12561388533 is a `hidden beast` number, since 1 + 2 + 561 + 3 + 8 + 85 + 3 + 3 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 2728286289 + 9833102244 = 52233^2 + 99162^2 .

It is not a de Polignac number, because 12561388533 - 2¹ = 12561388531 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12561388531) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 7840266 + ... + 7841867.

It is an arithmetic number, because the mean of its divisors is an integer number (1529008065).

Almost surely, 2^12561388533 is an apocalyptic number.

It is an amenable number.

12561388533 is a deficient number, since it is larger than the sum of its proper divisors (5786708247).

12561388533 is a wasteful number, since it uses less digits than its factorization.

12561388533 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15682228 (or 15682225 counting only the distinct ones).

The product of its digits is 518400, while the sum is 45.

The spelling of 12561388533 in words is "twelve billion, five hundred sixty-one million, three hundred eighty-eight thousand, five hundred thirty-three".