161605566661655 has 8 divisors (see below), whose sum is σ = 197213572875600. Its totient is φ = 127093191408256.

The previous prime is 161605566661631. The next prime is 161605566661661. The reversal of 161605566661655 is 556166665506161.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 161605566661655 - 2¹² = 161605566657559 is a prime.

It is a super-2 number, since 2×161605566661655² (a number of 29 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 161605566661591 and 161605566661600.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 273907739810 + ... + 273907740399.

It is an arithmetic number, because the mean of its divisors is an integer number (24651696609450).

Almost surely, 2^{161605566661655} is an apocalyptic number.

161605566661655 is a deficient number, since it is larger than the sum of its proper divisors (35608006213945).

161605566661655 is an equidigital number, since it uses as much as digits as its factorization.

161605566661655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 547815480273.

The product of its (nonzero) digits is 174960000, while the sum is 65.

The spelling of 161605566661655 in words is "one hundred sixty-one trillion, six hundred five billion, five hundred sixty-six million, six hundred sixty-one thousand, six hundred fifty-five".