171125721931 has 2 divisors, whose sum is σ = 171125721932. Its totient is φ = 171125721930.

The previous prime is 171125721919. The next prime is 171125721947. The reversal of 171125721931 is 139127521171.

It is a happy number.

It is a weak prime.

It is an emirp because it is prime and its reverse (139127521171) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 171125721931 - 2²¹ = 171123624779 is a prime.

It is a super-2 number, since 2×171125721931² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (171125721901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85562860965 + 85562860966.

It is an arithmetic number, because the mean of its divisors is an integer number (85562860966).

Almost surely, 2^171125721931 is an apocalyptic number.

171125721931 is a deficient number, since it is larger than the sum of its proper divisors (1).

171125721931 is an equidigital number, since it uses as much as digits as its factorization.

171125721931 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 26460, while the sum is 40.

The spelling of 171125721931 in words is "one hundred seventy-one billion, one hundred twenty-five million, seven hundred twenty-one thousand, nine hundred thirty-one".