165904398 has 48 divisors (see below), whose sum is σ = 393537456. Its totient is φ = 50094720.

The previous prime is 165904393. The next prime is 165904421. The reversal of 165904398 is 893409561.

It is a happy number.

165904398 is a `hidden beast` number, since 16 + 590 + 43 + 9 + 8 = 666.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (165904391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 60636 + ... + 63312.

It is an arithmetic number, because the mean of its divisors is an integer number (8198697).

Almost surely, 2^165904398 is an apocalyptic number.

165904398 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 165904398, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (196768728).

165904398 is an abundant number, since it is smaller than the sum of its proper divisors (227633058).

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

165904398 is a wasteful number, since it uses less digits than its factorization.

165904398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3009 (or 3006 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The square root of 165904398 is about 12880.3881152704. The cubic root of 165904398 is about 549.4809405977.

The spelling of 165904398 in words is "one hundred sixty-five million, nine hundred four thousand, three hundred ninety-eight".