31861172 has 18 divisors (see below), whose sum is σ = 64860642. Its totient is φ = 13654704.

The previous prime is 31861171. The next prime is 31861177. The reversal of 31861172 is 27116813.

It can be written as a sum of positive squares in only one way, i.e., 29658916 + 2202256 = 5446^2 + 1484^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31861171) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 81083 + ... + 81474.

It is an arithmetic number, because the mean of its divisors is an integer number (3603369).

Almost surely, 2^31861172 is an apocalyptic number.

It is an amenable number.

31861172 is an abundant number, since it is smaller than the sum of its proper divisors (32999470).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31861172 is a wasteful number, since it uses less digits than its factorization.

31861172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162575 (or 162566 counting only the distinct ones).

The product of its digits is 2016, while the sum is 29.

The square root of 31861172 is about 5644.5701342086. The cubic root of 31861172 is about 317.0204287803.

Adding to 31861172 its reverse (27116813), we get a palindrome (58977985).

The spelling of 31861172 in words is "thirty-one million, eight hundred sixty-one thousand, one hundred seventy-two".