31161856 has 60 divisors (see below), whose sum is σ = 68573736. Its totient is φ = 14136320.

The previous prime is 31161847. The next prime is 31161857. The reversal of 31161856 is 65816113.

It is a super-2 number, since 2×31161856² = 1942122538729472, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31161857) 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, 61701 + ... + 62203.

Almost surely, 2^31161856 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31161856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34286868).

31161856 is an abundant number, since it is smaller than the sum of its proper divisors (37411880).

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

31161856 is an equidigital number, since it uses as much as digits as its factorization.

31161856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 543 (or 516 counting only the distinct ones).

The product of its digits is 4320, while the sum is 31.

The square root of 31161856 is about 5582.2805375581. The cubic root of 31161856 is about 314.6838383173.

Adding to 31161856 its reverse (65816113), we get a palindrome (96977969).

The spelling of 31161856 in words is "thirty-one million, one hundred sixty-one thousand, eight hundred fifty-six".