31315540 has 48 divisors (see below), whose sum is σ = 67692240. Its totient is φ = 12165120.

The previous prime is 31315519. The next prime is 31315541. The reversal of 31315540 is 4551313.

It is a happy number.

It can be written as a sum of positive squares in 8 ways, for example, as 156816 + 31158724 = 396^2 + 5582^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31315541) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 129820 + ... + 130060.

It is an arithmetic number, because the mean of its divisors is an integer number (1410255).

Almost surely, 2^31315540 is an apocalyptic number.

It is an amenable number.

31315540 is an abundant number, since it is smaller than the sum of its proper divisors (36376700).

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

31315540 is a wasteful number, since it uses less digits than its factorization.

31315540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 412 (or 410 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 22.

The square root of 31315540 is about 5596.0289491746. The cubic root of 31315540 is about 315.2003093137.

Adding to 31315540 its reverse (4551313), we get a palindrome (35866853).

The spelling of 31315540 in words is "thirty-one million, three hundred fifteen thousand, five hundred forty".