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31221120 = 2735723101
BaseRepresentation
bin111011100011…
…0010110000000
32011202012022210
41313012112000
530443033440
63033102120
7526242450
oct167062600
964665283
1031221120
1116694987
12a557940
136611a48
144209d60
152b1aa80
hex1dc6580

31221120 has 256 divisors, whose sum is σ = 119854080. Its totient is φ = 6758400.

The previous prime is 31221107. The next prime is 31221149. The reversal of 31221120 is 2112213.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 31221096 and 31221105.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 309070 + ... + 309170.

It is an arithmetic number, because the mean of its divisors is an integer number (468180).

Almost surely, 231221120 is an apocalyptic number.

31221120 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 31221120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (59927040).

31221120 is an abundant number, since it is smaller than the sum of its proper divisors (88632960).

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

31221120 is a wasteful number, since it uses less digits than its factorization.

31221120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 12.

The square root of 31221120 is about 5587.5862409452. The cubic root of 31221120 is about 314.8832018479.

Adding to 31221120 its reverse (2112213), we get a palindrome (33333333).

The spelling of 31221120 in words is "thirty-one million, two hundred twenty-one thousand, one hundred twenty".