661173166238 has 16 divisors (see below), whose sum is σ = 1068062747136. Its totient is φ = 305152907040.

The previous prime is 661173166217. The next prime is 661173166259. The reversal of 661173166238 is 832661371166.

It is an interprime number because it is at equal distance from previous prime (661173166217) and next prime (661173166259).

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, 3156620 + ... + 3359552.

It is an arithmetic number, because the mean of its divisors is an integer number (66753921696).

Almost surely, 2^661173166238 is an apocalyptic number.

661173166238 is a deficient number, since it is larger than the sum of its proper divisors (406889580898).

661173166238 is a wasteful number, since it uses less digits than its factorization.

661173166238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328259.

The product of its digits is 1306368, while the sum is 50.

The spelling of 661173166238 in words is "six hundred sixty-one billion, one hundred seventy-three million, one hundred sixty-six thousand, two hundred thirty-eight".