661363173 has 12 divisors (see below), whose sum is σ = 966813120. Its totient is φ = 435596136.

The previous prime is 661363151. The next prime is 661363187. The reversal of 661363173 is 371363166.

661363173 is a `hidden beast` number, since 6 + 6 + 13 + 631 + 7 + 3 = 666.

It is not a de Polignac number, because 661363173 - 2⁵ = 661363141 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (661363133) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 441933 + ... + 443426.

It is an arithmetic number, because the mean of its divisors is an integer number (80567760).

Almost surely, 2^661363173 is an apocalyptic number.

It is an amenable number.

661363173 is a deficient number, since it is larger than the sum of its proper divisors (305449947).

661363173 is a wasteful number, since it uses less digits than its factorization.

661363173 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 885448 (or 885445 counting only the distinct ones).

The product of its digits is 40824, while the sum is 36.

The square root of 661363173 is about 25716.9821907626. The cubic root of 661363173 is about 871.2577804025.

The spelling of 661363173 in words is "six hundred sixty-one million, three hundred sixty-three thousand, one hundred seventy-three".