31321040 has 40 divisors (see below), whose sum is σ = 73522080. Its totient is φ = 12407936.

The previous prime is 31321033. The next prime is 31321049. The reversal of 31321040 is 4012313.

It is a tau number, because it is divible by the number of its divisors (40).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31321049) 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, 6731 + ... + 10389.

It is an arithmetic number, because the mean of its divisors is an integer number (1838052).

Almost surely, 2^31321040 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 31321040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36761040).

31321040 is an abundant number, since it is smaller than the sum of its proper divisors (42201040).

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

31321040 is a wasteful number, since it uses less digits than its factorization.

31321040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3779 (or 3773 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 31321040 is about 5596.5203475017. The cubic root of 31321040 is about 315.2187612837.

Adding to 31321040 its reverse (4012313), we get a palindrome (35333353).

The spelling of 31321040 in words is "thirty-one million, three hundred twenty-one thousand, forty".