165537421 has 16 divisors (see below), whose sum is σ = 193651200. Its totient is φ = 138572208.

The previous prime is 165537389. The next prime is 165537439. The reversal of 165537421 is 124735561.

It is a cyclic number.

It is not a de Polignac number, because 165537421 - 2⁵ = 165537389 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 (165537461) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 66090 + ... + 68548.

It is an arithmetic number, because the mean of its divisors is an integer number (12103200).

Almost surely, 2^165537421 is an apocalyptic number.

It is an amenable number.

165537421 is a deficient number, since it is larger than the sum of its proper divisors (28113779).

165537421 is a wasteful number, since it uses less digits than its factorization.

165537421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2688.

The product of its digits is 25200, while the sum is 34.

The square root of 165537421 is about 12866.1346565315. The cubic root of 165537421 is about 549.0754947866.

The spelling of 165537421 in words is "one hundred sixty-five million, five hundred thirty-seven thousand, four hundred twenty-one".