172206509 has 2 divisors, whose sum is σ = 172206510. Its totient is φ = 172206508.

The previous prime is 172206493. The next prime is 172206511. The reversal of 172206509 is 905602271.

172206509 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 134629609 + 37576900 = 11603^2 + 6130^2 .

It is a cyclic number.

It is not a de Polignac number, because 172206509 - 2⁴ = 172206493 is a prime.

Together with 172206511, 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 (172206409) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86103254 + 86103255.

It is an arithmetic number, because the mean of its divisors is an integer number (86103255).

Almost surely, 2^172206509 is an apocalyptic number.

It is an amenable number.

172206509 is a deficient number, since it is larger than the sum of its proper divisors (1).

172206509 is an equidigital number, since it uses as much as digits as its factorization.

172206509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 7560, while the sum is 32.

The square root of 172206509 is about 13122.7477686649. The cubic root of 172206509 is about 556.3522570244.

The spelling of 172206509 in words is "one hundred seventy-two million, two hundred six thousand, five hundred nine".