31231133213220 has 288 divisors, whose sum is σ = 97706739128544. Its totient is φ = 8069947392000.

The previous prime is 31231133213173. The next prime is 31231133213257. The reversal of 31231133213220 is 2231233113213.

31231133213220 is a `hidden beast` number, since 3 + 1 + 2 + 3 + 1 + 1 + 332 + 1 + 322 + 0 = 666.

It can be written as a sum of positive squares in 16 ways, for example, as 6903609110784 + 24327524102436 = 2627472^2 + 4932294^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 689512894 + ... + 689558186.

It is an arithmetic number, because the mean of its divisors is an integer number (339259510863).

Almost surely, 2^{31231133213220} is an apocalyptic number.

31231133213220 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 31231133213220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48853369564272).

31231133213220 is an abundant number, since it is smaller than the sum of its proper divisors (66475605915324).

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

31231133213220 is a wasteful number, since it uses less digits than its factorization.

31231133213220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45983 (or 45978 counting only the distinct ones).

The product of its (nonzero) digits is 3888, while the sum is 27.

Adding to 31231133213220 its reverse (2231233113213), we get a palindrome (33462366326433).

The spelling of 31231133213220 in words is "thirty-one trillion, two hundred thirty-one billion, one hundred thirty-three million, two hundred thirteen thousand, two hundred twenty".