165221445 has 16 divisors (see below), whose sum is σ = 265389120. Its totient is φ = 87773184.

The previous prime is 165221429. The next prime is 165221449. The reversal of 165221445 is 544122561.

It is not a de Polignac number, because 165221445 - 2⁴ = 165221429 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165221449) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17575 + ... + 25284.

It is an arithmetic number, because the mean of its divisors is an integer number (16586820).

Almost surely, 2^165221445 is an apocalyptic number.

165221445 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

165221445 is a deficient number, since it is larger than the sum of its proper divisors (100167675).

165221445 is a wasteful number, since it uses less digits than its factorization.

165221445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43124.

The product of its digits is 9600, while the sum is 30.

The square root of 165221445 is about 12853.8494234218. The cubic root of 165221445 is about 548.7259158557.

The spelling of 165221445 in words is "one hundred sixty-five million, two hundred twenty-one thousand, four hundred forty-five".