181821050557 has 8 divisors (see below), whose sum is σ = 185194181952. Its totient is φ = 178470482400.

The previous prime is 181821050531. The next prime is 181821050573. The reversal of 181821050557 is 755050128181.

181821050557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 181821050557 - 2³¹ = 179673566909 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181821050507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5624544 + ... + 5656777.

It is an arithmetic number, because the mean of its divisors is an integer number (23149272744).

Almost surely, 2^181821050557 is an apocalyptic number.

It is an amenable number.

181821050557 is a deficient number, since it is larger than the sum of its proper divisors (3373131395).

181821050557 is a wasteful number, since it uses less digits than its factorization.

181821050557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11281619.

The product of its (nonzero) digits is 112000, while the sum is 43.

The spelling of 181821050557 in words is "one hundred eighty-one billion, eight hundred twenty-one million, fifty thousand, five hundred fifty-seven".