161317454721 has 16 divisors (see below), whose sum is σ = 215450689536. Its totient is φ = 107364727376.

The previous prime is 161317454693. The next prime is 161317454723. The reversal of 161317454721 is 127454713161.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 161317454721 - 2⁹ = 161317454209 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161317454723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5326006 + ... + 5356208.

It is an arithmetic number, because the mean of its divisors is an integer number (13465668096).

Almost surely, 2^161317454721 is an apocalyptic number.

It is an amenable number.

161317454721 is a deficient number, since it is larger than the sum of its proper divisors (54133234815).

161317454721 is a wasteful number, since it uses less digits than its factorization.

161317454721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33132.

The product of its digits is 141120, while the sum is 42.

The spelling of 161317454721 in words is "one hundred sixty-one billion, three hundred seventeen million, four hundred fifty-four thousand, seven hundred twenty-one".