12181531 has 2 divisors, whose sum is σ = 12181532. Its totient is φ = 12181530.

The previous prime is 12181529. The next prime is 12181567. The reversal of 12181531 is 13518121.

12181531 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 12181531 - 2¹ = 12181529 is a prime.

It is a super-2 number, since 2×12181531² = 296779395007922, which contains 22 as substring.

Together with 12181529, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (12181031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6090765 + 6090766.

It is an arithmetic number, because the mean of its divisors is an integer number (6090766).

Almost surely, 2^12181531 is an apocalyptic number.

12181531 is a deficient number, since it is larger than the sum of its proper divisors (1).

12181531 is an equidigital number, since it uses as much as digits as its factorization.

12181531 is an evil number, because the sum of its binary digits is even.

The product of its digits is 240, while the sum is 22.

The square root of 12181531 is about 3490.2050083054. The cubic root of 12181531 is about 230.0915262701.

Adding to 12181531 its reverse (13518121), we get a palindrome (25699652).

The spelling of 12181531 in words is "twelve million, one hundred eighty-one thousand, five hundred thirty-one".