18181890002 has 4 divisors (see below), whose sum is σ = 27272835006. Its totient is φ = 9090945000.

The previous prime is 18181889983. The next prime is 18181890017. The reversal of 18181890002 is 20009818181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 20009818181 = 113 ⋅177078037.

It can be written as a sum of positive squares in only one way, i.e., 16586606521 + 1595283481 = 128789^2 + 39941^2 .

It is a super-2 number, since 2×18181890002² (a number of 21 digits) contains 22 as substring.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4545472499 + ... + 4545472502.

Almost surely, 2^18181890002 is an apocalyptic number.

18181890002 is a deficient number, since it is larger than the sum of its proper divisors (9090945004).

18181890002 is an equidigital number, since it uses as much as digits as its factorization.

18181890002 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9090945003.

The product of its (nonzero) digits is 9216, while the sum is 38.

The spelling of 18181890002 in words is "eighteen billion, one hundred eighty-one million, eight hundred ninety thousand, two".