165221504 has 64 divisors (see below), whose sum is σ = 398338560. Its totient is φ = 66637824.

The previous prime is 165221501. The next prime is 165221519. The reversal of 165221504 is 405122561.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (165221501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9809 + ... + 20655.

It is an arithmetic number, because the mean of its divisors is an integer number (6224040).

Almost surely, 2^165221504 is an apocalyptic number.

165221504 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165221504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (199169280).

165221504 is an abundant number, since it is smaller than the sum of its proper divisors (233117056).

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

165221504 is a wasteful number, since it uses less digits than its factorization.

165221504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10885 (or 10873 counting only the distinct ones).

The product of its (nonzero) digits is 2400, while the sum is 26.

The square root of 165221504 is about 12853.8517184539. The cubic root of 165221504 is about 548.7259811717.

The spelling of 165221504 in words is "one hundred sixty-five million, two hundred twenty-one thousand, five hundred four".