161651565060561 has 24 divisors (see below), whose sum is σ = 248689183410304. Its totient is φ = 104855069222640.

The previous prime is 161651565060523. The next prime is 161651565060649. The reversal of 161651565060561 is 165060565156161.

161651565060561 is a `hidden beast` number, since 1 + 6 + 1 + 6 + 5 + 15 + 6 + 5 + 0 + 60 + 561 = 666.

It is not a de Polignac number, because 161651565060561 - 2¹⁵ = 161651565027793 is a prime.

It is a super-2 number, since 2×161651565060561² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 161651565060498 and 161651565060507.

It is not an unprimeable number, because it can be changed into a prime (161651565065561) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8989623145 + ... + 8989641126.

Almost surely, 2^{161651565060561} is an apocalyptic number.

It is an amenable number.

161651565060561 is a deficient number, since it is larger than the sum of its proper divisors (87037618349743).

161651565060561 is an equidigital number, since it uses as much as digits as its factorization.

161651565060561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17979264323 (or 17979264311 counting only the distinct ones).

The product of its (nonzero) digits is 4860000, while the sum is 54.

The spelling of 161651565060561 in words is "one hundred sixty-one trillion, six hundred fifty-one billion, five hundred sixty-five million, sixty thousand, five hundred sixty-one".