661173707 has 4 divisors (see below), whose sum is σ = 700066296. Its totient is φ = 622281120.

The previous prime is 661173703. The next prime is 661173713. The reversal of 661173707 is 707371166.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 707371166 = 2 ⋅353685583.

It is a cyclic number.

It is not a de Polignac number, because 661173707 - 2² = 661173703 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (661173701) 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 3 ways as a sum of consecutive naturals, for example, 19446269 + ... + 19446302.

It is an arithmetic number, because the mean of its divisors is an integer number (175016574).

Almost surely, 2^661173707 is an apocalyptic number.

661173707 is a deficient number, since it is larger than the sum of its proper divisors (38892589).

661173707 is a wasteful number, since it uses less digits than its factorization.

661173707 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38892588.

The product of its (nonzero) digits is 37044, while the sum is 38.

The square root of 661173707 is about 25713.2982520718. The cubic root of 661173707 is about 871.1745737272.

The spelling of 661173707 in words is "six hundred sixty-one million, one hundred seventy-three thousand, seven hundred seven".