181381210561 has 8 divisors (see below), whose sum is σ = 182410928640. Its totient is φ = 180353749632.

The previous prime is 181381210553. The next prime is 181381210567. The reversal of 181381210561 is 165012183181.

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 181381210561 - 2³ = 181381210553 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 181381210561.

It is not an unprimeable number, because it can be changed into a prime (181381210567) 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, 402985 + ... + 724678.

It is an arithmetic number, because the mean of its divisors is an integer number (22801366080).

Almost surely, 2^181381210561 is an apocalyptic number.

It is an amenable number.

181381210561 is a deficient number, since it is larger than the sum of its proper divisors (1029718079).

181381210561 is a wasteful number, since it uses less digits than its factorization.

181381210561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1128575.

The product of its (nonzero) digits is 11520, while the sum is 37.

The spelling of 181381210561 in words is "one hundred eighty-one billion, three hundred eighty-one million, two hundred ten thousand, five hundred sixty-one".