161970656561 has 16 divisors (see below), whose sum is σ = 185917790208. Its totient is φ = 138226770000.

The previous prime is 161970656527. The next prime is 161970656569. The reversal of 161970656561 is 165656079161.

It is a cyclic number.

It is not a de Polignac number, because 161970656561 - 2¹⁴ = 161970640177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161970656569) 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 15 ways as a sum of consecutive naturals, for example, 1693526 + ... + 1786608.

It is an arithmetic number, because the mean of its divisors is an integer number (11619861888).

Almost surely, 2^161970656561 is an apocalyptic number.

It is an amenable number.

161970656561 is a deficient number, since it is larger than the sum of its proper divisors (23947133647).

161970656561 is an equidigital number, since it uses as much as digits as its factorization.

161970656561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94172.

The product of its (nonzero) digits is 2041200, while the sum is 53.

The spelling of 161970656561 in words is "one hundred sixty-one billion, nine hundred seventy million, six hundred fifty-six thousand, five hundred sixty-one".