171857506249 has 45 divisors (see below), whose sum is σ = 205564237809. Its totient is φ = 143569380240.

The previous prime is 171857506237. The next prime is 171857506267. The reversal of 171857506249 is 942605758171.

The square root of 171857506249 is 414557.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 85209696649 + 86647809600 = 291907^2 + 294360^2 .

It is not a de Polignac number, because 171857506249 - 2⁵ = 171857506217 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 171857506249.

It is not an unprimeable number, because it can be changed into a prime (171857506229) by changing a digit.

It is a polite number, since it can be written in 44 ways as a sum of consecutive naturals, for example, 770661352 + ... + 770661574.

Almost surely, 2^171857506249 is an apocalyptic number.

171857506249 is the 414557-th square number.

171857506249 is the 207279-th centered octagonal number.

It is an amenable number.

171857506249 is a deficient number, since it is larger than the sum of its proper divisors (33706731560).

171857506249 is an frugal number, since it uses more digits than its factorization.

171857506249 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 520 (or 247 counting only the distinct ones).

The product of its (nonzero) digits is 4233600, while the sum is 55.

The spelling of 171857506249 in words is "one hundred seventy-one billion, eight hundred fifty-seven million, five hundred six thousand, two hundred forty-nine".