81018369 has 6 divisors (see below), whose sum is σ = 117026546. Its totient is φ = 54012240.

The previous prime is 81018359. The next prime is 81018383. The reversal of 81018369 is 96381018.

It can be written as a sum of positive squares in only one way, i.e., 55130625 + 25887744 = 7425^2 + 5088^2 .

It is not a de Polignac number, because 81018369 - 2⁷ = 81018241 is a prime.

It is a super-2 number, since 2×81018369² = 13127952230840322, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (81018349) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4501012 + ... + 4501029.

Almost surely, 2^81018369 is an apocalyptic number.

It is an amenable number.

81018369 is a deficient number, since it is larger than the sum of its proper divisors (36008177).

81018369 is a wasteful number, since it uses less digits than its factorization.

81018369 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9002047 (or 9002044 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 36.

The square root of 81018369 is about 9001.0204421499. The cubic root of 81018369 is about 432.7075756354.

The spelling of 81018369 in words is "eighty-one million, eighteen thousand, three hundred sixty-nine".