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81816120 = 23325227267
BaseRepresentation
bin1001110000001…
…10101000111000
312200221200121200
410320012220320
5131421103440
612041334200
72012265651
oct470065070
9180850550
1081816120
1142201731
1223497360
1313c47c09
14ac1a528
1572b1c30
hex4e06a38

81816120 has 48 divisors (see below), whose sum is σ = 265903560. Its totient is φ = 21817536.

The previous prime is 81816107. The next prime is 81816157. The reversal of 81816120 is 2161818.

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 11 ways as a sum of consecutive naturals, for example, 113274 + ... + 113993.

Almost surely, 281816120 is an apocalyptic number.

It is an amenable number.

81816120 is an abundant number, since it is smaller than the sum of its proper divisors (184087440).

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

81816120 is a wasteful number, since it uses less digits than its factorization.

81816120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 227284 (or 227277 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 81816120 is about 9045.2263653266. The cubic root of 81816120 is about 434.1231643758.

Adding to 81816120 its reverse (2161818), we get a palindrome (83977938).

The spelling of 81816120 in words is "eighty-one million, eight hundred sixteen thousand, one hundred twenty".

Divisors: 1 2 3 4 5 6 8 9 10 12 15 18 20 24 30 36 40 45 60 72 90 120 180 360 227267 454534 681801 909068 1136335 1363602 1818136 2045403 2272670 2727204 3409005 4090806 4545340 5454408 6818010 8181612 9090680 10227015 13636020 16363224 20454030 27272040 40908060 81816120