31211323220 has 108 divisors (see below), whose sum is σ = 83806590420. Its totient is φ = 9728167680.

The previous prime is 31211323177. The next prime is 31211323259. The reversal of 31211323220 is 2232311213.

It can be written as a sum of positive squares in 2 ways, for example, as 8480936464 + 22730386756 = 92092^2 + 150766^2 .

It is a super-2 number, since 2×31211323220² (a number of 22 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 31211323192 and 31211323201.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 13025 + ... + 250184.

Almost surely, 2^31211323220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31211323220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41903295210).

31211323220 is an abundant number, since it is smaller than the sum of its proper divisors (52595267200).

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

31211323220 is a wasteful number, since it uses less digits than its factorization.

31211323220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 263254 (or 263234 counting only the distinct ones).

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

Adding to 31211323220 its reverse (2232311213), we get a palindrome (33443634433).

The spelling of 31211323220 in words is "thirty-one billion, two hundred eleven million, three hundred twenty-three thousand, two hundred twenty".