660321997 has 2 divisors, whose sum is σ = 660321998. Its totient is φ = 660321996.

The previous prime is 660321929. The next prime is 660322009. The reversal of 660321997 is 799123066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 450245961 + 210076036 = 21219^2 + 14494^2 .

It is a cyclic number.

It is not a de Polignac number, because 660321997 - 2²³ = 651933389 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660322997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330160998 + 330160999.

It is an arithmetic number, because the mean of its divisors is an integer number (330160999).

Almost surely, 2^660321997 is an apocalyptic number.

It is an amenable number.

660321997 is a deficient number, since it is larger than the sum of its proper divisors (1).

660321997 is an equidigital number, since it uses as much as digits as its factorization.

660321997 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 122472, while the sum is 43.

The square root of 660321997 is about 25696.7312512701. The cubic root of 660321997 is about 870.8003367599.

The spelling of 660321997 in words is "six hundred sixty million, three hundred twenty-one thousand, nine hundred ninety-seven".