181638120557504 has 224 divisors, whose sum is σ = 413558448024960. Its totient is φ = 78410186883072.

The previous prime is 181638120557423. The next prime is 181638120557507. The reversal of 181638120557504 is 405755021836181.

It is a happy number.

181638120557504 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a self number, because there is not a number n which added to its sum of digits gives 181638120557504.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181638120557507) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 14637605252 + ... + 14637617660.

It is an arithmetic number, because the mean of its divisors is an integer number (1846243071540).

Almost surely, 2^{181638120557504} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 181638120557504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (206779224012480).

181638120557504 is an abundant number, since it is smaller than the sum of its proper divisors (231920327467456).

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

181638120557504 is a wasteful number, since it uses less digits than its factorization.

181638120557504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18815 (or 18805 counting only the distinct ones).

The product of its (nonzero) digits is 8064000, while the sum is 56.

The spelling of 181638120557504 in words is "one hundred eighty-one trillion, six hundred thirty-eight billion, one hundred twenty million, five hundred fifty-seven thousand, five hundred four".