172008639581 has 2 divisors, whose sum is σ = 172008639582. Its totient is φ = 172008639580.

The previous prime is 172008639563. The next prime is 172008639601. The reversal of 172008639581 is 185936800271.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 169023765625 + 2984873956 = 411125^2 + 54634^2 .

It is an emirp because it is prime and its reverse (185936800271) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 172008639581 - 2¹⁴ = 172008623197 is a prime.

It is a super-2 number, since 2×172008639581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172008639181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86004319790 + 86004319791.

It is an arithmetic number, because the mean of its divisors is an integer number (86004319791).

Almost surely, 2^172008639581 is an apocalyptic number.

It is an amenable number.

172008639581 is a deficient number, since it is larger than the sum of its proper divisors (1).

172008639581 is an equidigital number, since it uses as much as digits as its factorization.

172008639581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 725760, while the sum is 50.

The spelling of 172008639581 in words is "one hundred seventy-two billion, eight million, six hundred thirty-nine thousand, five hundred eighty-one".