81018018 has 12 divisors (see below), whose sum is σ = 175539078. Its totient is φ = 27006000.

The previous prime is 81018017. The next prime is 81018019. The reversal of 81018018 is 81081018.

It is an interprime number because it is at equal distance from previous prime (81018017) and next prime (81018019).

It can be written as a sum of positive squares in only one way, i.e., 69505569 + 11512449 = 8337^2 + 3393^2 .

It is a junction number, because it is equal to n+sod(n) for n = 81017982 and 81018000.

It is not an unprimeable number, because it can be changed into a prime (81018013) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2250483 + ... + 2250518.

Almost surely, 2^81018018 is an apocalyptic number.

81018018 is an abundant number, since it is smaller than the sum of its proper divisors (94521060).

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

81018018 is a wasteful number, since it uses less digits than its factorization.

81018018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4501009 (or 4501006 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 27.

The square root of 81018018 is about 9001.0009443395. Note that the first 3 decimals coincide. The cubic root of 81018018 is about 432.7069507541.

The spelling of 81018018 in words is "eighty-one million, eighteen thousand, eighteen".