165651551 has 8 divisors (see below), whose sum is σ = 180032160. Its totient is φ = 151504992.

The previous prime is 165651529. The next prime is 165651571. The reversal of 165651551 is 155156561.

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 165651551 - 2⁶ = 165651487 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 (165651571) 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, 57035 + ... + 59868.

It is an arithmetic number, because the mean of its divisors is an integer number (22504020).

Almost surely, 2^165651551 is an apocalyptic number.

165651551 is a deficient number, since it is larger than the sum of its proper divisors (14380609).

165651551 is a wasteful number, since it uses less digits than its factorization.

165651551 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117025.

The product of its digits is 22500, while the sum is 35.

The square root of 165651551 is about 12870.5691793331. The cubic root of 165651551 is about 549.2016527466.

The spelling of 165651551 in words is "one hundred sixty-five million, six hundred fifty-one thousand, five hundred fifty-one".