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81405216000 = 28335394219
BaseRepresentation
bin100101111010000100…
…0010000010100000000
321210010021021102222000
41023310020100110000
52313204213403000
6101221432144000
75611203630153
oct1136410202400
9253107242860
1081405216000
1131584138719
121393a538000
1378a42bb784
143d23647c9a
1521b6a44000
hex12f4210500

81405216000 has 288 divisors, whose sum is σ = 300433660800. Its totient is φ = 21707827200.

The previous prime is 81405215999. The next prime is 81405216019. The reversal of 81405216000 is 61250418.

81405216000 is a `hidden beast` number, since 8 + 1 + 4 + 0 + 52 + 1 + 600 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (27).

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, 816891 + ... + 911109.

Almost surely, 281405216000 is an apocalyptic number.

81405216000 is a gapful number since it is divisible by the number (80) 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 81405216000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150216830400).

81405216000 is an abundant number, since it is smaller than the sum of its proper divisors (219028444800).

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

81405216000 is an equidigital number, since it uses as much as digits as its factorization.

81405216000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94259 (or 94229 counting only the distinct ones).

The product of its (nonzero) digits is 1920, while the sum is 27.

Adding to 81405216000 its reverse (61250418), we get a palindrome (81466466418).

The spelling of 81405216000 in words is "eighty-one billion, four hundred five million, two hundred sixteen thousand".