165557557 has 4 divisors (see below), whose sum is σ = 180608256. Its totient is φ = 150506860.

The previous prime is 165557551. The next prime is 165557591. The reversal of 165557557 is 755755561.

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 165557557 - 2²⁷ = 31339829 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 (165557551) 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, 7525333 + ... + 7525354.

It is an arithmetic number, because the mean of its divisors is an integer number (45152064).

Almost surely, 2^165557557 is an apocalyptic number.

It is an amenable number.

165557557 is a deficient number, since it is larger than the sum of its proper divisors (15050699).

165557557 is a wasteful number, since it uses less digits than its factorization.

165557557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15050698.

The product of its digits is 918750, while the sum is 46.

The square root of 165557557 is about 12866.9171521387. The cubic root of 165557557 is about 549.0977570961.

The spelling of 165557557 in words is "one hundred sixty-five million, five hundred fifty-seven thousand, five hundred fifty-seven".