665520636 has 24 divisors (see below), whose sum is σ = 1694052864. Its totient is φ = 201672880.

The previous prime is 665520631. The next prime is 665520637. The reversal of 665520636 is 636025566.

It is a junction number, because it is equal to n+sod(n) for n = 665520594 and 665520603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665520631) 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 7 ways as a sum of consecutive naturals, for example, 2520780 + ... + 2521043.

It is an arithmetic number, because the mean of its divisors is an integer number (70585536).

Almost surely, 2^665520636 is an apocalyptic number.

665520636 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

665520636 is an abundant number, since it is smaller than the sum of its proper divisors (1028532228).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

665520636 is a wasteful number, since it uses less digits than its factorization.

665520636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5041841 (or 5041839 counting only the distinct ones).

The product of its (nonzero) digits is 194400, while the sum is 39.

The square root of 665520636 is about 25797.6866404722. The cubic root of 665520636 is about 873.0796026237.

The spelling of 665520636 in words is "six hundred sixty-five million, five hundred twenty thousand, six hundred thirty-six".