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81081000 = 23345371113
BaseRepresentation
bin1001101010100…
…11001010101000
312122120100020000
410311103022220
5131224043000
612013503000
72003114520
oct465231250
9178510200
1081081000
114184a3a0
12231a1a60
1313a4b430
14aaa8680
1571b9000
hex4d532a8

81081000 has 640 divisors, whose sum is σ = 380540160. Its totient is φ = 15552000.

The previous prime is 81080977. The next prime is 81081001. The reversal of 81081000 is 18018.

It is a happy number.

It is a super-2 number, since 2×810810002 = 13148257122000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81081001) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 6236994 + ... + 6237006.

It is an arithmetic number, because the mean of its divisors is an integer number (594594).

Almost surely, 281081000 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 81081000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (190270080).

81081000 is an abundant number, since it is smaller than the sum of its proper divisors (299459160).

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

81081000 is a wasteful number, since it uses less digits than its factorization.

81081000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 81081000 is about 9004.4988755621. The cubic root of 81081000 is about 432.8190480010.

Adding to 81081000 its reverse (18018), we get a palindrome (81099018).

It can be divided in two parts, 810 and 81000, that multiplied together give a 4-th power (65610000 = 904).

The spelling of 81081000 in words is "eighty-one million, eighty-one thousand".