81040340511 has 40 divisors (see below), whose sum is σ = 133552479984. Its totient is φ = 48654587520.

The previous prime is 81040340497. The next prime is 81040340531. The reversal of 81040340511 is 11504304018.

It is a happy number.

81040340511 is a `hidden beast` number, since 8 + 104 + 0 + 3 + 40 + 511 = 666.

It is not a de Polignac number, because 81040340511 - 2¹⁰ = 81040339487 is a prime.

It is a super-2 number, since 2×81040340511² (a number of 23 digits) contains 22 as substring.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81040340531) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 895381 + ... + 981726.

Almost surely, 2^81040340511 is an apocalyptic number.

81040340511 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

81040340511 is a deficient number, since it is larger than the sum of its proper divisors (52512139473).

81040340511 is a wasteful number, since it uses less digits than its factorization.

81040340511 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1877173 (or 1877164 counting only the distinct ones).

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

Adding to 81040340511 its reverse (11504304018), we get a palindrome (92544644529).

The spelling of 81040340511 in words is "eighty-one billion, forty million, three hundred forty thousand, five hundred eleven".