12129531 has 4 divisors (see below), whose sum is σ = 16172712. Its totient is φ = 8086352.

The previous prime is 12129521. The next prime is 12129539. The reversal of 12129531 is 13592121.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13592121 = 3 ⋅4530707.

It is a cyclic number.

It is not a de Polignac number, because 12129531 - 2⁵ = 12129499 is a prime.

It is a super-2 number, since 2×12129531² = 294251044559922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (12129539) 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, 2021586 + ... + 2021591.

It is an arithmetic number, because the mean of its divisors is an integer number (4043178).

Almost surely, 2^12129531 is an apocalyptic number.

12129531 is a deficient number, since it is larger than the sum of its proper divisors (4043181).

12129531 is an equidigital number, since it uses as much as digits as its factorization.

12129531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4043180.

The product of its digits is 540, while the sum is 24.

The square root of 12129531 is about 3482.7476222086. The cubic root of 12129531 is about 229.7636576647.

The spelling of 12129531 in words is "twelve million, one hundred twenty-nine thousand, five hundred thirty-one".