172403909 has 2 divisors, whose sum is σ = 172403910. Its totient is φ = 172403908.

The previous prime is 172403821. The next prime is 172403911. The reversal of 172403909 is 909304271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158130625 + 14273284 = 12575^2 + 3778^2 .

It is a cyclic number.

It is not a de Polignac number, because 172403909 - 2¹² = 172399813 is a prime.

Together with 172403911, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172400909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86201954 + 86201955.

It is an arithmetic number, because the mean of its divisors is an integer number (86201955).

Almost surely, 2^172403909 is an apocalyptic number.

It is an amenable number.

172403909 is a deficient number, since it is larger than the sum of its proper divisors (1).

172403909 is an equidigital number, since it uses as much as digits as its factorization.

172403909 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13608, while the sum is 35.

The square root of 172403909 is about 13130.2669051318. The cubic root of 172403909 is about 556.5647577001.

The spelling of 172403909 in words is "one hundred seventy-two million, four hundred three thousand, nine hundred nine".