181557315987 has 8 divisors (see below), whose sum is σ = 250423884240. Its totient is φ = 116864479200.

The previous prime is 181557315959. The next prime is 181557315997. The reversal of 181557315987 is 789513755181.

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

It is not a de Polignac number, because 181557315987 - 2¹⁶ = 181557250451 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 181557315987.

It is not an unprimeable number, because it can be changed into a prime (181557315917) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1043432764 + ... + 1043432937.

It is an arithmetic number, because the mean of its divisors is an integer number (31302985530).

Almost surely, 2^181557315987 is an apocalyptic number.

181557315987 is a deficient number, since it is larger than the sum of its proper divisors (68866568253).

181557315987 is a wasteful number, since it uses less digits than its factorization.

181557315987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2086865733.

The product of its digits is 10584000, while the sum is 60.

The spelling of 181557315987 in words is "one hundred eighty-one billion, five hundred fifty-seven million, three hundred fifteen thousand, nine hundred eighty-seven".