172113509 has 2 divisors, whose sum is σ = 172113510. Its totient is φ = 172113508.

The previous prime is 172113437. The next prime is 172113523. The reversal of 172113509 is 905311271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 121660900 + 50452609 = 11030^2 + 7103^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172113509 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172113709) 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, 86056754 + 86056755.

It is an arithmetic number, because the mean of its divisors is an integer number (86056755).

Almost surely, 2^172113509 is an apocalyptic number.

It is an amenable number.

172113509 is a deficient number, since it is larger than the sum of its proper divisors (1).

172113509 is an equidigital number, since it uses as much as digits as its factorization.

172113509 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1890, while the sum is 29.

The square root of 172113509 is about 13119.2038249278. The cubic root of 172113509 is about 556.2520864459.

The spelling of 172113509 in words is "one hundred seventy-two million, one hundred thirteen thousand, five hundred nine".