165421660 has 24 divisors (see below), whose sum is σ = 352573200. Its totient is φ = 65180544.

The previous prime is 165421621. The next prime is 165421687. The reversal of 165421660 is 66124561.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 60385 + ... + 63064.

It is an arithmetic number, because the mean of its divisors is an integer number (14690550).

Almost surely, 2^165421660 is an apocalyptic number.

165421660 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

165421660 is an abundant number, since it is smaller than the sum of its proper divisors (187151540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165421660 is a wasteful number, since it uses less digits than its factorization.

165421660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123525 (or 123523 counting only the distinct ones).

The product of its (nonzero) digits is 8640, while the sum is 31.

The square root of 165421660 is about 12861.6351993049. The cubic root of 165421660 is about 548.9474746890.

The spelling of 165421660 in words is "one hundred sixty-five million, four hundred twenty-one thousand, six hundred sixty".