31821081438 has 64 divisors (see below), whose sum is σ = 66882336768. Its totient is φ = 10080322560.

The previous prime is 31821081437. The next prime is 31821081521. The reversal of 31821081438 is 83418012813.

It is a junction number, because it is equal to n+sod(n) for n = 31821081396 and 31821081405.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31821081431) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4195906 + ... + 4203482.

It is an arithmetic number, because the mean of its divisors is an integer number (1045036512).

Almost surely, 2^31821081438 is an apocalyptic number.

31821081438 is an abundant number, since it is smaller than the sum of its proper divisors (35061255330).

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

31821081438 is a wasteful number, since it uses less digits than its factorization.

31821081438 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8017.

The product of its (nonzero) digits is 36864, while the sum is 39.

The spelling of 31821081438 in words is "thirty-one billion, eight hundred twenty-one million, eighty-one thousand, four hundred thirty-eight".