31220332440 has 128 divisors (see below), whose sum is σ = 102218630400. Its totient is φ = 7565381120.

The previous prime is 31220332433. The next prime is 31220332463. The reversal of 31220332440 is 4423302213.

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 31220332440.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5175346 + ... + 5181374.

It is an arithmetic number, because the mean of its divisors is an integer number (798583050).

Almost surely, 2^31220332440 is an apocalyptic number.

31220332440 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 31220332440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (51109315200).

31220332440 is an abundant number, since it is smaller than the sum of its proper divisors (70998297960).

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

31220332440 is a wasteful number, since it uses less digits than its factorization.

31220332440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9977 (or 9973 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 24.

Adding to 31220332440 its reverse (4423302213), we get a palindrome (35643634653).

The spelling of 31220332440 in words is "thirty-one billion, two hundred twenty million, three hundred thirty-two thousand, four hundred forty".