31223040 has 144 divisors (see below), whose sum is σ = 102428928. Its totient is φ = 8101888.

The previous prime is 31223021. The next prime is 31223041. The reversal of 31223040 is 4032213.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31223041) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 180394 + ... + 180566.

It is an arithmetic number, because the mean of its divisors is an integer number (711312).

Almost surely, 2^31223040 is an apocalyptic number.

31223040 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31223040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51214464).

31223040 is an abundant number, since it is smaller than the sum of its proper divisors (71205888).

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

31223040 is a wasteful number, since it uses less digits than its factorization.

31223040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 244 (or 230 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 31223040 is about 5587.7580477326. The cubic root of 31223040 is about 314.8896564888.

Adding to 31223040 its reverse (4032213), we get a palindrome (35255253).

The spelling of 31223040 in words is "thirty-one million, two hundred twenty-three thousand, forty".