81113505 has 32 divisors (see below), whose sum is σ = 141989760. Its totient is φ = 39214080.

The previous prime is 81113491. The next prime is 81113507. The reversal of 81113505 is 50531118.

It is not a de Polignac number, because 81113505 - 2¹⁰ = 81112481 is a prime.

It is not an unprimeable number, because it can be changed into a prime (81113507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 97431 + ... + 98259.

It is an arithmetic number, because the mean of its divisors is an integer number (4437180).

Almost surely, 2^81113505 is an apocalyptic number.

It is an amenable number.

81113505 is a deficient number, since it is larger than the sum of its proper divisors (60876255).

81113505 is a wasteful number, since it uses less digits than its factorization.

81113505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1441.

The product of its (nonzero) digits is 600, while the sum is 24.

The square root of 81113505 is about 9006.3036257945. The cubic root of 81113505 is about 432.8768786622.

It can be divided in two parts, 81113 and 505, that added together give a palindrome (81618).

The spelling of 81113505 in words is "eighty-one million, one hundred thirteen thousand, five hundred five".