171687205381 has 2 divisors, whose sum is σ = 171687205382. Its totient is φ = 171687205380.

The previous prime is 171687205351. The next prime is 171687205523. The reversal of 171687205381 is 183502786171.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 121515685281 + 50171520100 = 348591^2 + 223990^2 .

It is an emirp because it is prime and its reverse (183502786171) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 171687205381 - 2⁹ = 171687204869 is a prime.

It is a super-2 number, since 2×171687205381² (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 (171687205301) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85843602690 + 85843602691.

It is an arithmetic number, because the mean of its divisors is an integer number (85843602691).

Almost surely, 2^171687205381 is an apocalyptic number.

It is an amenable number.

171687205381 is a deficient number, since it is larger than the sum of its proper divisors (1).

171687205381 is an equidigital number, since it uses as much as digits as its factorization.

171687205381 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 564480, while the sum is 49.

The spelling of 171687205381 in words is "one hundred seventy-one billion, six hundred eighty-seven million, two hundred five thousand, three hundred eighty-one".