161618651785 has 8 divisors (see below), whose sum is σ = 194123812680. Its totient is φ = 129173967744.

The previous prime is 161618651783. The next prime is 161618651839. The reversal of 161618651785 is 587156816161.

It can be written as a sum of positive squares in 4 ways, for example, as 3192363001 + 158426288784 = 56501^2 + 398028^2 .

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 161618651785 - 2¹ = 161618651783 is a prime.

It is a super-2 number, since 2×161618651785² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161618651783) 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, 15113332 + ... + 15124021.

It is an arithmetic number, because the mean of its divisors is an integer number (24265476585).

Almost surely, 2^161618651785 is an apocalyptic number.

It is an amenable number.

161618651785 is a deficient number, since it is larger than the sum of its proper divisors (32505160895).

161618651785 is a wasteful number, since it uses less digits than its factorization.

161618651785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30238427.

The product of its digits is 2419200, while the sum is 55.

The spelling of 161618651785 in words is "one hundred sixty-one billion, six hundred eighteen million, six hundred fifty-one thousand, seven hundred eighty-five".