660549997 has 2 divisors, whose sum is σ = 660549998. Its totient is φ = 660549996.

The previous prime is 660549947. The next prime is 660550003. The reversal of 660549997 is 799945066.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 566963721 + 93586276 = 23811^2 + 9674^2 .

It is a cyclic number.

It is not a de Polignac number, because 660549997 - 2²⁷ = 526332269 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (660549947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 330274998 + 330274999.

It is an arithmetic number, because the mean of its divisors is an integer number (330274999).

Almost surely, 2^660549997 is an apocalyptic number.

It is an amenable number.

660549997 is a deficient number, since it is larger than the sum of its proper divisors (1).

660549997 is an equidigital number, since it uses as much as digits as its factorization.

660549997 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3674160, while the sum is 55.

The square root of 660549997 is about 25701.1672303030. The cubic root of 660549997 is about 870.9005503076.

The spelling of 660549997 in words is "six hundred sixty million, five hundred forty-nine thousand, nine hundred ninety-seven".