161868672908644 has 27 divisors (see below), whose sum is σ = 306736972989867. Its totient is φ = 74708465592384.

The previous prime is 161868672908617. The next prime is 161868672908651. The reversal of 161868672908644 is 446809276868161.

The square root of 161868672908644 is 12722762.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 19508457918244 + 142360214990400 = 4416838^2 + 11931480^2 .

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 330547144 + ... + 331036480.

Almost surely, 2^{161868672908644} is an apocalyptic number.

161868672908644 is the 12722762-nd square number.

It is an amenable number.

161868672908644 is a deficient number, since it is larger than the sum of its proper divisors (144868300081223).

161868672908644 is an frugal number, since it uses more digits than its factorization.

161868672908644 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 978704 (or 489352 counting only the distinct ones).

The product of its (nonzero) digits is 1337720832, while the sum is 76.

The spelling of 161868672908644 in words is "one hundred sixty-one trillion, eight hundred sixty-eight billion, six hundred seventy-two million, nine hundred eight thousand, six hundred forty-four".