161640167985 has 12 divisors (see below), whose sum is σ = 280176291252. Its totient is φ = 86208089568.

The previous prime is 161640167981. The next prime is 161640168037. The reversal of 161640167985 is 589761046161.

161640167985 is a `hidden beast` number, since 1 + 616 + 4 + 0 + 16 + 7 + 9 + 8 + 5 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 119174086656 + 42466081329 = 345216^2 + 206073^2 .

It is not a de Polignac number, because 161640167985 - 2² = 161640167981 is a prime.

It is a super-2 number, since 2×161640167985² (a number of 23 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161640167981) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1796001822 + ... + 1796001911.

It is an arithmetic number, because the mean of its divisors is an integer number (23348024271).

Almost surely, 2^161640167985 is an apocalyptic number.

161640167985 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

161640167985 is a deficient number, since it is larger than the sum of its proper divisors (118536123267).

161640167985 is a wasteful number, since it uses less digits than its factorization.

161640167985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3592003744 (or 3592003741 counting only the distinct ones).

The product of its (nonzero) digits is 2177280, while the sum is 54.

The spelling of 161640167985 in words is "one hundred sixty-one billion, six hundred forty million, one hundred sixty-seven thousand, nine hundred eighty-five".