31112720 has 40 divisors (see below), whose sum is σ = 76595544. Its totient is φ = 11712512.

The previous prime is 31112713. The next prime is 31112729. The reversal of 31112720 is 2721113.

It can be written as a sum of positive squares in 4 ways, for example, as 12588304 + 18524416 = 3548^2 + 4304^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31112729) 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 7 ways as a sum of consecutive naturals, for example, 10079 + ... + 12798.

Almost surely, 2^31112720 is an apocalyptic number.

It is an amenable number.

31112720 is an abundant number, since it is smaller than the sum of its proper divisors (45482824).

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

31112720 is a wasteful number, since it uses less digits than its factorization.

31112720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22907 (or 22901 counting only the distinct ones).

The product of its (nonzero) digits is 84, while the sum is 17.

The square root of 31112720 is about 5577.8777326148. The cubic root of 31112720 is about 314.5183535315.

Adding to 31112720 its reverse (2721113), we get a palindrome (33833833).

It can be divided in two parts, 311 and 12720, that added together give a palindrome (13031).

The spelling of 31112720 in words is "thirty-one million, one hundred twelve thousand, seven hundred twenty".