165606551 has 8 divisors (see below), whose sum is σ = 180921600. Its totient is φ = 150334840.

The previous prime is 165606523. The next prime is 165606563. The reversal of 165606551 is 155606561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 165606551 - 2¹⁰ = 165605527 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 (165606751) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2561 + ... + 18378.

It is an arithmetic number, because the mean of its divisors is an integer number (22615200).

Almost surely, 2^165606551 is an apocalyptic number.

165606551 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

165606551 is a deficient number, since it is larger than the sum of its proper divisors (15315049).

165606551 is a wasteful number, since it uses less digits than its factorization.

165606551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21669.

The product of its (nonzero) digits is 27000, while the sum is 35.

The square root of 165606551 is about 12868.8208861574. The cubic root of 165606551 is about 549.1519171974.

The spelling of 165606551 in words is "one hundred sixty-five million, six hundred six thousand, five hundred fifty-one".