31220431440 has 80 divisors (see below), whose sum is σ = 105581831616. Its totient is φ = 7568588800.

The previous prime is 31220431409. The next prime is 31220431447. The reversal of 31220431440 is 4413402213.

It is a tau number, because it is divible by the number of its divisors (80).

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 31220431440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31220431447) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 5910321 + ... + 5915600.

Almost surely, 2^31220431440 is an apocalyptic number.

31220431440 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31220431440 is an abundant number, since it is smaller than the sum of its proper divisors (74361400176).

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

31220431440 is a wasteful number, since it uses less digits than its factorization.

31220431440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11825948 (or 11825942 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

Adding to 31220431440 its reverse (4413402213), we get a palindrome (35633833653).

The spelling of 31220431440 in words is "thirty-one billion, two hundred twenty million, four hundred thirty-one thousand, four hundred forty".