156242209 has 2 divisors, whose sum is σ = 156242210. Its totient is φ = 156242208.

The previous prime is 156242179. The next prime is 156242221. The reversal of 156242209 is 902242651.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 115089984 + 41152225 = 10728^2 + 6415^2 .

It is an emirp because it is prime and its reverse (902242651) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 156242209 - 2²⁷ = 22024481 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (156242249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 78121104 + 78121105.

It is an arithmetic number, because the mean of its divisors is an integer number (78121105).

Almost surely, 2^156242209 is an apocalyptic number.

It is an amenable number.

156242209 is a deficient number, since it is larger than the sum of its proper divisors (1).

156242209 is an equidigital number, since it uses as much as digits as its factorization.

156242209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 156242209 is about 12499.6883561151. The cubic root of 156242209 is about 538.5997202522.

The spelling of 156242209 in words is "one hundred fifty-six million, two hundred forty-two thousand, two hundred nine".