165605651 has 4 divisors (see below), whose sum is σ = 166171152. Its totient is φ = 165040152.

The previous prime is 165605639. The next prime is 165605663. The reversal of 165605651 is 156506561.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (165605639) and next prime (165605663).

It is a cyclic number.

It is not a de Polignac number, because 165605651 - 2¹⁴ = 165589267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165605621) 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, 282311 + ... + 282896.

It is an arithmetic number, because the mean of its divisors is an integer number (41542788).

Almost surely, 2^165605651 is an apocalyptic number.

165605651 is a deficient number, since it is larger than the sum of its proper divisors (565501).

165605651 is an equidigital number, since it uses as much as digits as its factorization.

165605651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 565500.

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

The square root of 165605651 is about 12868.7859178712. The cubic root of 165605651 is about 549.1509223945.

The spelling of 165605651 in words is "one hundred sixty-five million, six hundred five thousand, six hundred fifty-one".