665551699 has 2 divisors, whose sum is σ = 665551700. Its totient is φ = 665551698.

The previous prime is 665551673. The next prime is 665551709. The reversal of 665551699 is 996155566.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-665551699 is a prime.

It is not a weakly prime, because it can be changed into another prime (665551609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332775849 + 332775850.

It is an arithmetic number, because the mean of its divisors is an integer number (332775850).

Almost surely, 2^665551699 is an apocalyptic number.

665551699 is a deficient number, since it is larger than the sum of its proper divisors (1).

665551699 is an equidigital number, since it uses as much as digits as its factorization.

665551699 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2187000, while the sum is 52.

The square root of 665551699 is about 25798.2886835542. The cubic root of 665551699 is about 873.0931859990.

The spelling of 665551699 in words is "six hundred sixty-five million, five hundred fifty-one thousand, six hundred ninety-nine".