665898408 has 160 divisors (see below), whose sum is σ = 2161853760. Its totient is φ = 187557120.

The previous prime is 665898407. The next prime is 665898419. The reversal of 665898408 is 804898566.

It is a happy number.

665898408 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (665898403) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 330123 + ... + 332133.

It is an arithmetic number, because the mean of its divisors is an integer number (13511586).

Almost surely, 2^665898408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665898408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1080926880).

665898408 is an abundant number, since it is smaller than the sum of its proper divisors (1495955352).

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

665898408 is a wasteful number, since it uses less digits than its factorization.

665898408 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2109 (or 2096 counting only the distinct ones).

The product of its (nonzero) digits is 3317760, while the sum is 54.

The square root of 665898408 is about 25805.0074210414. The cubic root of 665898408 is about 873.2447678707.

The spelling of 665898408 in words is "six hundred sixty-five million, eight hundred ninety-eight thousand, four hundred eight".