81161244 has 48 divisors (see below), whose sum is σ = 210903840. Its totient is φ = 26991360.

The previous prime is 81161243. The next prime is 81161251. The reversal of 81161244 is 44216118.

It is a happy number.

81161244 is a `hidden beast` number, since 8 + 1 + 1 + 612 + 44 = 666.

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 (81161243) 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 15 ways as a sum of consecutive naturals, for example, 91684 + ... + 92564.

It is an arithmetic number, because the mean of its divisors is an integer number (4393830).

Almost surely, 2^81161244 is an apocalyptic number.

It is an amenable number.

81161244 is an abundant number, since it is smaller than the sum of its proper divisors (129742596).

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

81161244 is a wasteful number, since it uses less digits than its factorization.

81161244 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1747 (or 1739 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 81161244 is about 9008.9535463338. The cubic root of 81161244 is about 432.9617846078.

The spelling of 81161244 in words is "eighty-one million, one hundred sixty-one thousand, two hundred forty-four".