81071040 has 56 divisors (see below), whose sum is σ = 257403600. Its totient is φ = 21618688.

The previous prime is 81071017. The next prime is 81071057. The reversal of 81071040 is 4017018.

81071040 = T₄₂₄₀ + T₄₂₄₁ + ... + T₄₂₄₈.

It is a junction number, because it is equal to n+sod(n) for n = 81070998 and 81071016.

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 7 ways as a sum of consecutive naturals, for example, 41265 + ... + 43184.

Almost surely, 2^81071040 is an apocalyptic number.

81071040 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

81071040 is an abundant number, since it is smaller than the sum of its proper divisors (176332560).

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

81071040 is a wasteful number, since it uses less digits than its factorization.

81071040 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84469 (or 84459 counting only the distinct ones).

The product of its (nonzero) digits is 224, while the sum is 21.

The square root of 81071040 is about 9003.9458017027. The cubic root of 81071040 is about 432.8013247602.

Adding to 81071040 its reverse (4017018), we get a palindrome (85088058).

The spelling of 81071040 in words is "eighty-one million, seventy-one thousand, forty".