172129607509 has 2 divisors, whose sum is σ = 172129607510. Its totient is φ = 172129607508.

The previous prime is 172129607389. The next prime is 172129607543. The reversal of 172129607509 is 905706921271.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 161756796100 + 10372811409 = 402190^2 + 101847^2 .

It is a cyclic number.

It is not a de Polignac number, because 172129607509 - 2⁷ = 172129607381 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172129607569) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86064803754 + 86064803755.

It is an arithmetic number, because the mean of its divisors is an integer number (86064803755).

Almost surely, 2^172129607509 is an apocalyptic number.

It is an amenable number.

172129607509 is a deficient number, since it is larger than the sum of its proper divisors (1).

172129607509 is an equidigital number, since it uses as much as digits as its factorization.

172129607509 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 476280, while the sum is 49.

The spelling of 172129607509 in words is "one hundred seventy-two billion, one hundred twenty-nine million, six hundred seven thousand, five hundred nine".