31161312 has 288 divisors, whose sum is σ = 115577280. Its totient is φ = 7741440.

The previous prime is 31161307. The next prime is 31161331. The reversal of 31161312 is 21316113.

It is a tau number, because it is divible by the number of its divisors (288).

It is a super-2 number, since 2×31161312² = 1942054731122688, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 760012 + ... + 760052.

It is an arithmetic number, because the mean of its divisors is an integer number (401310).

Almost surely, 2^31161312 is an apocalyptic number.

31161312 is a gapful number since it is divisible by the number (32) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31161312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (57788640).

31161312 is an abundant number, since it is smaller than the sum of its proper divisors (84415968).

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

31161312 is a wasteful number, since it uses less digits than its factorization.

31161312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 106 (or 95 counting only the distinct ones).

The product of its digits is 108, while the sum is 18.

The square root of 31161312 is about 5582.2318117398. The cubic root of 31161312 is about 314.6820071362.

Adding to 31161312 its reverse (21316113), we get a palindrome (52477425).

The spelling of 31161312 in words is "thirty-one million, one hundred sixty-one thousand, three hundred twelve".