665550556 has 12 divisors (see below), whose sum is σ = 1270596600. Its totient is φ = 302522960.

The previous prime is 665550553. The next prime is 665550559. The reversal of 665550556 is 655055566.

It is an interprime number because it is at equal distance from previous prime (665550553) and next prime (665550559).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665550553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7563031 + ... + 7563118.

It is an arithmetic number, because the mean of its divisors is an integer number (105883050).

Almost surely, 2^665550556 is an apocalyptic number.

It is an amenable number.

665550556 is a deficient number, since it is larger than the sum of its proper divisors (605046044).

665550556 is a wasteful number, since it uses less digits than its factorization.

665550556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15126164 (or 15126162 counting only the distinct ones).

The product of its (nonzero) digits is 675000, while the sum is 43.

The square root of 665550556 is about 25798.2665309125. The cubic root of 665550556 is about 873.0926861901.

The spelling of 665550556 in words is "six hundred sixty-five million, five hundred fifty thousand, five hundred fifty-six".