165672121 has 4 divisors (see below), whose sum is σ = 165711744. Its totient is φ = 165632500.

The previous prime is 165672107. The next prime is 165672127. The reversal of 165672121 is 121276561.

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 165672121 - 2¹¹ = 165670073 is a prime.

It is an alternating number because its digits alternate between odd and even.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (165672127) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12685 + ... + 22186.

It is an arithmetic number, because the mean of its divisors is an integer number (41427936).

Almost surely, 2^165672121 is an apocalyptic number.

It is an amenable number.

165672121 is a deficient number, since it is larger than the sum of its proper divisors (39623).

165672121 is an equidigital number, since it uses as much as digits as its factorization.

165672121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39622.

The product of its digits is 5040, while the sum is 31.

The square root of 165672121 is about 12871.3682644853. The cubic root of 165672121 is about 549.2243844191.

The spelling of 165672121 in words is "one hundred sixty-five million, six hundred seventy-two thousand, one hundred twenty-one".