31221132120 has 384 divisors, whose sum is σ = 110480198400. Its totient is φ = 7620480000.

The previous prime is 31221132119. The next prime is 31221132169. The reversal of 31221132120 is 2123112213.

31221132120 is a `hidden beast` number, since 312 + 2 + 11 + 321 + 20 = 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 = 31221132093 and 31221132102.

It is a congruent number.

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, 29705595 + ... + 29706645.

It is an arithmetic number, because the mean of its divisors is an integer number (287708850).

Almost surely, 2^31221132120 is an apocalyptic number.

31221132120 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 31221132120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (55240099200).

31221132120 is an abundant number, since it is smaller than the sum of its proper divisors (79259066280).

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

31221132120 is a wasteful number, since it uses less digits than its factorization.

31221132120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1231 (or 1224 counting only the distinct ones).

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

Adding to 31221132120 its reverse (2123112213), we get a palindrome (33344244333).

The spelling of 31221132120 in words is "thirty-one billion, two hundred twenty-one million, one hundred thirty-two thousand, one hundred twenty".