660173993 has 2 divisors, whose sum is σ = 660173994. Its totient is φ = 660173992.

The previous prime is 660173977. The next prime is 660173999. The reversal of 660173993 is 399371066.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 635443264 + 24730729 = 25208^2 + 4973^2 .

It is a cyclic number.

It is not a de Polignac number, because 660173993 - 2⁴ = 660173977 is a prime.

It is not a weakly prime, because it can be changed into another prime (660173999) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330086996 + 330086997.

It is an arithmetic number, because the mean of its divisors is an integer number (330086997).

Almost surely, 2^660173993 is an apocalyptic number.

It is an amenable number.

660173993 is a deficient number, since it is larger than the sum of its proper divisors (1).

660173993 is an equidigital number, since it uses as much as digits as its factorization.

660173993 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 183708, while the sum is 44.

The square root of 660173993 is about 25693.8512683482. The cubic root of 660173993 is about 870.7352717543.

It can be divided in two parts, 660173 and 993, that added together give a palindrome (661166).

The spelling of 660173993 in words is "six hundred sixty million, one hundred seventy-three thousand, nine hundred ninety-three".