665679650 has 12 divisors (see below), whose sum is σ = 1238164242. Its totient is φ = 266271840.

The previous prime is 665679643. The next prime is 665679653. The reversal of 665679650 is 56976566.

It can be written as a sum of positive squares in 3 ways, for example, as 510353281 + 155326369 = 22591^2 + 12463^2 .

It is a Harshad number since it is a multiple of its sum of digits (50), and also a Moran number because the ratio is a prime number: 13313593 = 665679650 / (6 + 6 + 5 + 6 + 7 + 9 + 6 + 5 + 0).

It is not an unprimeable number, because it can be changed into a prime (665679653) 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 5 ways as a sum of consecutive naturals, for example, 6656747 + ... + 6656846.

Almost surely, 2^665679650 is an apocalyptic number.

665679650 is a deficient number, since it is larger than the sum of its proper divisors (572484592).

665679650 is a wasteful number, since it uses less digits than its factorization.

665679650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13313605 (or 13313600 counting only the distinct ones).

The product of its (nonzero) digits is 2041200, while the sum is 50.

The square root of 665679650 is about 25800.7683994101. The cubic root of 665679650 is about 873.1491325610.

The spelling of 665679650 in words is "six hundred sixty-five million, six hundred seventy-nine thousand, six hundred fifty".