31708161 has 9 divisors (see below), whose sum is σ = 45825091. Its totient is φ = 21127512.

The previous prime is 31708153. The next prime is 31708199. The reversal of 31708161 is 16180713.

The square root of 31708161 is 5631.

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

It can be written as a sum of positive squares in only one way, i.e., 19847025 + 11861136 = 4455^2 + 3444^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 31708161 - 2³ = 31708153 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (31708121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 15955 + ... + 17831.

Almost surely, 2^31708161 is an apocalyptic number.

31708161 is the 5631-st square number.

31708161 is the 2816-th centered octagonal number.

It is an amenable number.

31708161 is a deficient number, since it is larger than the sum of its proper divisors (14116930).

31708161 is an frugal number, since it uses more digits than its factorization.

31708161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3760 (or 1880 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The cubic root of 31708161 is about 316.5121248996.

Adding to 31708161 its reverse (16180713), we get a palindrome (47888874).

The spelling of 31708161 in words is "thirty-one million, seven hundred eight thousand, one hundred sixty-one".