165505657 has 4 divisors (see below), whose sum is σ = 166290256. Its totient is φ = 164721060.

The previous prime is 165505651. The next prime is 165505661. The reversal of 165505657 is 756505561.

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 165505657 - 2²³ = 157117049 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165505651) 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 3 ways as a sum of consecutive naturals, for example, 391983 + ... + 392404.

It is an arithmetic number, because the mean of its divisors is an integer number (41572564).

Almost surely, 2^165505657 is an apocalyptic number.

It is an amenable number.

165505657 is a deficient number, since it is larger than the sum of its proper divisors (784599).

165505657 is an equidigital number, since it uses as much as digits as its factorization.

165505657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 784598.

The product of its (nonzero) digits is 157500, while the sum is 40.

The square root of 165505657 is about 12864.9001939385. The cubic root of 165505657 is about 549.0403729200.

The spelling of 165505657 in words is "one hundred sixty-five million, five hundred five thousand, six hundred fifty-seven".