665651047 has 2 divisors, whose sum is σ = 665651048. Its totient is φ = 665651046.

The previous prime is 665651033. The next prime is 665651071. The reversal of 665651047 is 740156566.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 665651047 - 2²⁷ = 531433319 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (665651347) 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 as a sum of consecutive naturals, namely, 332825523 + 332825524.

It is an arithmetic number, because the mean of its divisors is an integer number (332825524).

Almost surely, 2^665651047 is an apocalyptic number.

665651047 is a deficient number, since it is larger than the sum of its proper divisors (1).

665651047 is an equidigital number, since it uses as much as digits as its factorization.

665651047 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 151200, while the sum is 40.

The square root of 665651047 is about 25800.2140882590. The cubic root of 665651047 is about 873.1366265243.

The spelling of 665651047 in words is "six hundred sixty-five million, six hundred fifty-one thousand, forty-seven".