161171561605551 has 32 divisors (see below), whose sum is σ = 245674076779008. Its totient is φ = 92068293947520.

The previous prime is 161171561605541. The next prime is 161171561605601. The reversal of 161171561605551 is 155506165171161.

It is a happy number.

It is a de Polignac number, because none of the positive numbers 2^k-161171561605551 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 161171561605494 and 161171561605503.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161171561605501) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2995003321 + ... + 2995057133.

It is an arithmetic number, because the mean of its divisors is an integer number (7677314899344).

Almost surely, 2^{161171561605551} is an apocalyptic number.

161171561605551 is a deficient number, since it is larger than the sum of its proper divisors (84502515173457).

161171561605551 is a wasteful number, since it uses less digits than its factorization.

161171561605551 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 97231.

The product of its (nonzero) digits is 945000, while the sum is 51.

The spelling of 161171561605551 in words is "one hundred sixty-one trillion, one hundred seventy-one billion, five hundred sixty-one million, six hundred five thousand, five hundred fifty-one".