181546440138 has 48 divisors (see below), whose sum is σ = 454594645440. Its totient is φ = 51287594688.

The previous prime is 181546440133. The next prime is 181546440151. The reversal of 181546440138 is 831044645181.

181546440138 is a `hidden beast` number, since 1 + 8 + 15 + 464 + 40 + 138 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 181546440093 and 181546440102.

It is not an unprimeable number, because it can be changed into a prime (181546440133) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8083420 + ... + 8105847.

It is an arithmetic number, because the mean of its divisors is an integer number (9470721780).

Almost surely, 2^181546440138 is an apocalyptic number.

181546440138 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

181546440138 is an abundant number, since it is smaller than the sum of its proper divisors (273048205302).

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

181546440138 is a wasteful number, since it uses less digits than its factorization.

181546440138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16189371 (or 16189368 counting only the distinct ones).

The product of its (nonzero) digits is 368640, while the sum is 45.

The spelling of 181546440138 in words is "one hundred eighty-one billion, five hundred forty-six million, four hundred forty thousand, one hundred thirty-eight".