123172409 has 2 divisors, whose sum is σ = 123172410. Its totient is φ = 123172408.

The previous prime is 123172397. The next prime is 123172451. The reversal of 123172409 is 904271321.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 99940009 + 23232400 = 9997^2 + 4820^2 .

It is an emirp because it is prime and its reverse (904271321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 123172409 - 2¹⁶ = 123106873 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (123172499) 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 as a sum of consecutive naturals, namely, 61586204 + 61586205.

It is an arithmetic number, because the mean of its divisors is an integer number (61586205).

Almost surely, 2^123172409 is an apocalyptic number.

It is an amenable number.

123172409 is a deficient number, since it is larger than the sum of its proper divisors (1).

123172409 is an equidigital number, since it uses as much as digits as its factorization.

123172409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 29.

The square root of 123172409 is about 11098.3065825377. The cubic root of 123172409 is about 497.5512387148.

The spelling of 123172409 in words is "one hundred twenty-three million, one hundred seventy-two thousand, four hundred nine".