12521042581 has 4 divisors (see below), whose sum is σ = 12952802700. Its totient is φ = 12089282464.

The previous prime is 12521042551. The next prime is 12521042647. The reversal of 12521042581 is 18524012521.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 3847100625 + 8673941956 = 62025^2 + 93134^2 .

It is a cyclic number.

It is not a de Polignac number, because 12521042581 - 2⁹ = 12521042069 is a prime.

It is a super-2 number, since 2×12521042581² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12521042531) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 215880016 + ... + 215880073.

It is an arithmetic number, because the mean of its divisors is an integer number (3238200675).

Almost surely, 2^12521042581 is an apocalyptic number.

It is an amenable number.

12521042581 is a deficient number, since it is larger than the sum of its proper divisors (431760119).

12521042581 is an equidigital number, since it uses as much as digits as its factorization.

12521042581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 431760118.

The product of its (nonzero) digits is 6400, while the sum is 31.

The spelling of 12521042581 in words is "twelve billion, five hundred twenty-one million, forty-two thousand, five hundred eighty-one".