31221312032 has 48 divisors (see below), whose sum is σ = 63121034592. Its totient is φ = 15193167360.

The previous prime is 31221312029. The next prime is 31221312049. The reversal of 31221312032 is 23021312213.

It is a junction number, because it is equal to n+sod(n) for n = 31221311995 and 31221312013.

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 7 ways as a sum of consecutive naturals, for example, 346283 + ... + 427029.

It is an arithmetic number, because the mean of its divisors is an integer number (1315021554).

Almost surely, 2^31221312032 is an apocalyptic number.

31221312032 is a gapful number since it is divisible by the number (32) 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 31221312032, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31560517296).

31221312032 is an abundant number, since it is smaller than the sum of its proper divisors (31899722560).

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

31221312032 is a wasteful number, since it uses less digits than its factorization.

31221312032 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81081 (or 81073 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 20.

Adding to 31221312032 its reverse (23021312213), we get a palindrome (54242624245).

The spelling of 31221312032 in words is "thirty-one billion, two hundred twenty-one million, three hundred twelve thousand, thirty-two".