31211213220 has 240 divisors, whose sum is σ = 107214262848. Its totient is φ = 7537847040.

The previous prime is 31211213207. The next prime is 31211213237. The reversal of 31211213220 is 2231211213.

31211213220 is a `hidden beast` number, since 312 + 11 + 21 + 322 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 31211213193 and 31211213202.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 4932979 + ... + 4939301.

Almost surely, 2^31211213220 is an apocalyptic number.

31211213220 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 31211213220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53607131424).

31211213220 is an abundant number, since it is smaller than the sum of its proper divisors (76003049628).

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

31211213220 is a wasteful number, since it uses less digits than its factorization.

31211213220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6632 (or 6621 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 18.

Adding to 31211213220 its reverse (2231211213), we get a palindrome (33442424433).

The spelling of 31211213220 in words is "thirty-one billion, two hundred eleven million, two hundred thirteen thousand, two hundred twenty".