161817751405 has 8 divisors (see below), whose sum is σ = 194196524184. Its totient is φ = 129444052800.

The previous prime is 161817751391. The next prime is 161817751409. The reversal of 161817751405 is 504157718161.

It can be written as a sum of positive squares in 4 ways, for example, as 12589288804 + 149228462601 = 112202^2 + 386301^2 .

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

It is not a de Polignac number, because 161817751405 - 2²³ = 161809362797 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 (161817751409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1198026 + ... + 1326235.

It is an arithmetic number, because the mean of its divisors is an integer number (24274565523).

Almost surely, 2^161817751405 is an apocalyptic number.

It is an amenable number.

161817751405 is a deficient number, since it is larger than the sum of its proper divisors (32378772779).

161817751405 is a wasteful number, since it uses less digits than its factorization.

161817751405 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2537087.

The product of its (nonzero) digits is 235200, while the sum is 46.

The spelling of 161817751405 in words is "one hundred sixty-one billion, eight hundred seventeen million, seven hundred fifty-one thousand, four hundred five".