31012640 has 48 divisors (see below), whose sum is σ = 73664640. Its totient is φ = 12337920.

The previous prime is 31012633. The next prime is 31012649. The reversal of 31012640 is 4621013.

It is not an unprimeable number, because it can be changed into a prime (31012649) 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, 37835 + ... + 38645.

It is an arithmetic number, because the mean of its divisors is an integer number (1534680).

Almost surely, 2^31012640 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31012640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36832320).

31012640 is an abundant number, since it is smaller than the sum of its proper divisors (42652000).

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

31012640 is a wasteful number, since it uses less digits than its factorization.

31012640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1065 (or 1057 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 17.

The square root of 31012640 is about 5568.8993526549. The cubic root of 31012640 is about 314.1807551917.

Adding to 31012640 its reverse (4621013), we get a palindrome (35633653).

The spelling of 31012640 in words is "thirty-one million, twelve thousand, six hundred forty".