181991478050 has 18 divisors (see below), whose sum is σ = 338509760049. Its totient is φ = 72795384600.

The previous prime is 181991478049. The next prime is 181991478091. The reversal of 181991478050 is 50874199181.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 178351648489 + 3639829561 = 422317^2 + 60331^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=301655.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 181991477983 and 181991478001.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2986385 + ... + 3046715.

Almost surely, 2^181991478050 is an apocalyptic number.

181991478050 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

181991478050 is a deficient number, since it is larger than the sum of its proper divisors (156518281999).

181991478050 is an frugal number, since it uses more digits than its factorization.

181991478050 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120674 (or 60338 counting only the distinct ones).

The product of its (nonzero) digits is 725760, while the sum is 53.

The spelling of 181991478050 in words is "one hundred eighty-one billion, nine hundred ninety-one million, four hundred seventy-eight thousand, fifty".