12156509 has 2 divisors, whose sum is σ = 12156510. Its totient is φ = 12156508.

The previous prime is 12156499. The next prime is 12156511. The reversal of 12156509 is 90565121.

12156509 = 2012² + 2013² + 2014².

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12096484 + 60025 = 3478^2 + 245^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12156509 is a prime.

It is a super-2 number, since 2×12156509² = 295561422134162, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 12156511, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12156569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6078254 + 6078255.

It is an arithmetic number, because the mean of its divisors is an integer number (6078255).

Almost surely, 2^12156509 is an apocalyptic number.

It is an amenable number.

12156509 is a deficient number, since it is larger than the sum of its proper divisors (1).

12156509 is an equidigital number, since it uses as much as digits as its factorization.

12156509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2700, while the sum is 29.

The square root of 12156509 is about 3486.6185624470. The cubic root of 12156509 is about 229.9338751308.

The spelling of 12156509 in words is "twelve million, one hundred fifty-six thousand, five hundred nine".