31225640 has 32 divisors (see below), whose sum is σ = 70423560. Its totient is φ = 12460800.

The previous prime is 31225633. The next prime is 31225643. The reversal of 31225640 is 4652213.

It can be written as a sum of positive squares in 4 ways, for example, as 31114084 + 111556 = 5578^2 + 334^2 .

It is not an unprimeable number, because it can be changed into a prime (31225643) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25850 + ... + 27030.

Almost surely, 2^31225640 is an apocalyptic number.

It is an amenable number.

31225640 is an abundant number, since it is smaller than the sum of its proper divisors (39197920).

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

31225640 is a wasteful number, since it uses less digits than its factorization.

31225640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1853 (or 1849 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 31225640 is about 5587.9906943373. The cubic root of 31225640 is about 314.8983967266.

Adding to 31225640 its reverse (4652213), we get a palindrome (35877853).

It can be divided in two parts, 312 and 25640, that added together give a palindrome (25952).

The spelling of 31225640 in words is "thirty-one million, two hundred twenty-five thousand, six hundred forty".