31243540 has 24 divisors (see below), whose sum is σ = 67386312. Its totient is φ = 12159360.

The previous prime is 31243523. The next prime is 31243571. The reversal of 31243540 is 4534213.

It can be written as a sum of positive squares in 4 ways, for example, as 18369796 + 12873744 = 4286^2 + 3588^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20371 + ... + 21850.

It is an arithmetic number, because the mean of its divisors is an integer number (2807763).

Almost surely, 2^31243540 is an apocalyptic number.

It is an amenable number.

31243540 is an abundant number, since it is smaller than the sum of its proper divisors (36142772).

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

31243540 is a wasteful number, since it uses less digits than its factorization.

31243540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42267 (or 42265 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 31243540 is about 5589.5921139203. The cubic root of 31243540 is about 314.9585567380.

Adding to 31243540 its reverse (4534213), we get a palindrome (35777753).

The spelling of 31243540 in words is "thirty-one million, two hundred forty-three thousand, five hundred forty".