665550557 has 4 divisors (see below), whose sum is σ = 760629216. Its totient is φ = 570471900.

The previous prime is 665550553. The next prime is 665550559. The reversal of 665550557 is 755055566.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 665550557 - 2² = 665550553 is a prime.

It is a Duffinian number.

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, 47539319 + ... + 47539332.

It is an arithmetic number, because the mean of its divisors is an integer number (190157304).

Almost surely, 2^665550557 is an apocalyptic number.

It is an amenable number.

665550557 is a deficient number, since it is larger than the sum of its proper divisors (95078659).

665550557 is an equidigital number, since it uses as much as digits as its factorization.

665550557 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 95078658.

The product of its (nonzero) digits is 787500, while the sum is 44.

The square root of 665550557 is about 25798.2665502936. The cubic root of 665550557 is about 873.0926866274.

The spelling of 665550557 in words is "six hundred sixty-five million, five hundred fifty thousand, five hundred fifty-seven".