161145677081 has 4 divisors (see below), whose sum is σ = 161147186532. Its totient is φ = 161144167632.

The previous prime is 161145677051. The next prime is 161145677083. The reversal of 161145677081 is 180776541161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 82838049856 + 78307627225 = 287816^2 + 279835^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-161145677081 is a prime.

It is a super-2 number, since 2×161145677081² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161145677083) 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 3 ways as a sum of consecutive naturals, for example, 581306 + ... + 812531.

It is an arithmetic number, because the mean of its divisors is an integer number (40286796633).

Almost surely, 2^161145677081 is an apocalyptic number.

It is an amenable number.

161145677081 is a deficient number, since it is larger than the sum of its proper divisors (1509451).

161145677081 is a wasteful number, since it uses less digits than its factorization.

161145677081 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1509450.

The product of its (nonzero) digits is 282240, while the sum is 47.

The spelling of 161145677081 in words is "one hundred sixty-one billion, one hundred forty-five million, six hundred seventy-seven thousand, eighty-one".