1800000081 has 48 divisors (see below), whose sum is σ = 2973402432. Its totient is φ = 1039449600.

The previous prime is 1800000061. The next prime is 1800000109.

It is a happy number.

1800000081 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 1800000081 - 2⁵ = 1800000049 is a prime.

It is a super-2 number, since 2×1800000081² = 6480000583200013122, which contains 22 as substring.

1800000081 is a strobogrammatic number because it is the same when read upside-down.

1800000081 is a modest number, since divided by 81 gives 18 as remainder.

It is not an unprimeable number, because it can be changed into a prime (1800000011) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 169381 + ... + 179693.

It is an arithmetic number, because the mean of its divisors is an integer number (61945884).

Almost surely, 2^1800000081 is an apocalyptic number.

1800000081 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1800000081 is a deficient number, since it is larger than the sum of its proper divisors (1173402351).

1800000081 is a wasteful number, since it uses less digits than its factorization.

1800000081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10414 (or 10411 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 1800000081 is about 42426.4078257870. The cubic root of 1800000081 is about 1216.4404173613.

It can be divided in two parts, 18000000 and 81, that added together give a palindrome (18000081).

The spelling of 1800000081 in words is "one billion, eight hundred million, eighty-one", and thus it is an aban number.