81169744 has 20 divisors (see below), whose sum is σ = 157948596. Its totient is φ = 40408832.

The previous prime is 81169741. The next prime is 81169789. The reversal of 81169744 is 44796118.

It can be written as a sum of positive squares in 2 ways, for example, as 13601344 + 67568400 = 3688^2 + 8220^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81169697 and 81169706.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (81169741) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7159 + ... + 14614.

Almost surely, 2^81169744 is an apocalyptic number.

It is an amenable number.

81169744 is a deficient number, since it is larger than the sum of its proper divisors (76778852).

81169744 is a wasteful number, since it uses less digits than its factorization.

81169744 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22014 (or 22008 counting only the distinct ones).

The product of its digits is 48384, while the sum is 40.

The square root of 81169744 is about 9009.4252868871. The cubic root of 81169744 is about 432.9768987457.

It can be divided in two parts, 81 and 169744, that multiplied together give a square (13749264 = 3708²).

The spelling of 81169744 in words is "eighty-one million, one hundred sixty-nine thousand, seven hundred forty-four".