81063840 has 192 divisors, whose sum is σ = 300246912. Its totient is φ = 18124800.

The previous prime is 81063839. The next prime is 81063841. The reversal of 81063840 is 4836018.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (81063839) and next prime (81063841).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 81063798 and 81063807.

It is not an unprimeable number, because it can be changed into a prime (81063841) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 68050 + ... + 69230.

It is an arithmetic number, because the mean of its divisors is an integer number (1563786).

Almost surely, 2^81063840 is an apocalyptic number.

81063840 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 81063840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (150123456).

81063840 is an abundant number, since it is smaller than the sum of its proper divisors (219183072).

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

81063840 is a wasteful number, since it uses less digits than its factorization.

81063840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1223 (or 1215 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 30.

The square root of 81063840 is about 9003.5459681172. The cubic root of 81063840 is about 432.7885118750.

Adding to 81063840 its reverse (4836018), we get a palindrome (85899858).

The spelling of 81063840 in words is "eighty-one million, sixty-three thousand, eight hundred forty".