31132640 has 216 divisors, whose sum is σ = 98508312. Its totient is φ = 9192960.

The previous prime is 31132601. The next prime is 31132643. The reversal of 31132640 is 4623113.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31132643) 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 35 ways as a sum of consecutive naturals, for example, 1638551 + ... + 1638569.

It is an arithmetic number, because the mean of its divisors is an integer number (456057).

Almost surely, 2^31132640 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 31132640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49254156).

31132640 is an abundant number, since it is smaller than the sum of its proper divisors (67375672).

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

31132640 is a wasteful number, since it uses less digits than its factorization.

31132640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78 (or 44 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 31132640 is about 5579.6630722652. The cubic root of 31132640 is about 314.5854629429.

Adding to 31132640 its reverse (4623113), we get a palindrome (35755753).

The spelling of 31132640 in words is "thirty-one million, one hundred thirty-two thousand, six hundred forty".