173561661 has 48 divisors (see below), whose sum is σ = 312888576. Its totient is φ = 90263808.

The previous prime is 173561627. The next prime is 173561677. The reversal of 173561661 is 166165371.

173561661 is a `hidden beast` number, since 1 + 7 + 35 + 616 + 6 + 1 = 666.

It is not a de Polignac number, because 173561661 - 2⁷ = 173561533 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (173561261) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 58336 + ... + 61238.

It is an arithmetic number, because the mean of its divisors is an integer number (6518512).

Almost surely, 2^173561661 is an apocalyptic number.

It is an amenable number.

173561661 is a deficient number, since it is larger than the sum of its proper divisors (139326915).

173561661 is a wasteful number, since it uses less digits than its factorization.

173561661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3002 (or 2999 counting only the distinct ones).

The product of its digits is 22680, while the sum is 36.

The square root of 173561661 is about 13174.2802839472. The cubic root of 173561661 is about 557.8078210515.

The spelling of 173561661 in words is "one hundred seventy-three million, five hundred sixty-one thousand, six hundred sixty-one".