81349569 has 32 divisors (see below), whose sum is σ = 141469440. Its totient is φ = 45225216.

The previous prime is 81349561. The next prime is 81349571. The reversal of 81349569 is 96594318.

It is a happy number.

81349569 is a `hidden beast` number, since 81 + 3 + 4 + 9 + 569 = 666.

It is not a de Polignac number, because 81349569 - 2³ = 81349561 is a prime.

It is a super-2 number, since 2×81349569² = 13235504752971522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (81349561) 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, 1177 + ... + 12809.

It is an arithmetic number, because the mean of its divisors is an integer number (4420920).

Almost surely, 2^81349569 is an apocalyptic number.

It is an amenable number.

81349569 is a deficient number, since it is larger than the sum of its proper divisors (60119871).

81349569 is a wasteful number, since it uses less digits than its factorization.

81349569 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11686 (or 11680 counting only the distinct ones).

The product of its digits is 233280, while the sum is 45.

The square root of 81349569 is about 9019.3995919906. The cubic root of 81349569 is about 433.2964046768.

It can be divided in two parts, 81349 and 569, that added together give a palindrome (81918).

The spelling of 81349569 in words is "eighty-one million, three hundred forty-nine thousand, five hundred sixty-nine".