18010001081 has 4 divisors (see below), whose sum is σ = 18010634532. Its totient is φ = 18009367632.

The previous prime is 18010001041. The next prime is 18010001099.

18010001081 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 9040206400 + 8969794681 = 95080^2 + 94709^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18010001081 is a prime.

It is a super-2 number, since 2×18010001081² (a number of 21 digits) contains 22 as substring.

18010001081 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18010001011) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 271970 + ... + 331643.

It is an arithmetic number, because the mean of its divisors is an integer number (4502658633).

Almost surely, 2^18010001081 is an apocalyptic number.

It is an amenable number.

18010001081 is a deficient number, since it is larger than the sum of its proper divisors (633451).

18010001081 is an equidigital number, since it uses as much as digits as its factorization.

18010001081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 633450.

The product of its (nonzero) digits is 64, while the sum is 20.

It can be divided in two parts, 1801000 and 1081, that added together give a palindrome (1802081).

The spelling of 18010001081 in words is "eighteen billion, ten million, one thousand, eighty-one".