161021165 has 8 divisors (see below), whose sum is σ = 193329528. Its totient is φ = 128747520.

The previous prime is 161021131. The next prime is 161021173. The reversal of 161021165 is 561120161.

It can be written as a sum of positive squares in 4 ways, for example, as 1605289 + 159415876 = 1267^2 + 12626^2 .

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

It is not a de Polignac number, because 161021165 - 2¹⁶ = 160955629 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 161021165.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2945 + ... + 18185.

It is an arithmetic number, because the mean of its divisors is an integer number (24166191).

Almost surely, 2^161021165 is an apocalyptic number.

It is an amenable number.

161021165 is a deficient number, since it is larger than the sum of its proper divisors (32308363).

161021165 is a wasteful number, since it uses less digits than its factorization.

161021165 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17359.

The product of its (nonzero) digits is 360, while the sum is 23.

The square root of 161021165 is about 12689.4115308788. The cubic root of 161021165 is about 544.0360200432.

The spelling of 161021165 in words is "one hundred sixty-one million, twenty-one thousand, one hundred sixty-five".