665610651 has 12 divisors (see below), whose sum is σ = 964062112. Its totient is φ = 442529136.

The previous prime is 665610637. The next prime is 665610653. The reversal of 665610651 is 156016566.

It is not a de Polignac number, because 665610651 - 2⁹ = 665610139 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (665610653) 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 in 11 ways as a sum of consecutive naturals, for example, 97456 + ... + 104061.

Almost surely, 2^665610651 is an apocalyptic number.

665610651 is a deficient number, since it is larger than the sum of its proper divisors (298451461).

665610651 is a wasteful number, since it uses less digits than its factorization.

665610651 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 201890 (or 201887 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 665610651 is about 25799.4312146605. The cubic root of 665610651 is about 873.1189636458.

The spelling of 665610651 in words is "six hundred sixty-five million, six hundred ten thousand, six hundred fifty-one".