665787851 has 2 divisors, whose sum is σ = 665787852. Its totient is φ = 665787850.

The previous prime is 665787827. The next prime is 665787883. The reversal of 665787851 is 158787566.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665787851 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 665787793 and 665787802.

It is not a weakly prime, because it can be changed into another prime (665787821) 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, 332893925 + 332893926.

It is an arithmetic number, because the mean of its divisors is an integer number (332893926).

Almost surely, 2^665787851 is an apocalyptic number.

665787851 is a deficient number, since it is larger than the sum of its proper divisors (1).

665787851 is an equidigital number, since it uses as much as digits as its factorization.

665787851 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2822400, while the sum is 53.

The square root of 665787851 is about 25802.8651703643. The cubic root of 665787851 is about 873.1964378432.

The spelling of 665787851 in words is "six hundred sixty-five million, seven hundred eighty-seven thousand, eight hundred fifty-one".