12561531 has 4 divisors (see below), whose sum is σ = 16748712. Its totient is φ = 8374352.

The previous prime is 12561529. The next prime is 12561551. The reversal of 12561531 is 13516521.

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

It is a cyclic number.

It is not a de Polignac number, because 12561531 - 2¹ = 12561529 is a prime.

It is a super-2 number, since 2×12561531² = 315584122127922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (12561511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2093586 + ... + 2093591.

It is an arithmetic number, because the mean of its divisors is an integer number (4187178).

Almost surely, 2^12561531 is an apocalyptic number.

12561531 is a deficient number, since it is larger than the sum of its proper divisors (4187181).

12561531 is an equidigital number, since it uses as much as digits as its factorization.

12561531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4187180.

The product of its digits is 900, while the sum is 24.

The square root of 12561531 is about 3544.2250210730. The cubic root of 12561531 is about 232.4596206902.

The spelling of 12561531 in words is "twelve million, five hundred sixty-one thousand, five hundred thirty-one".