665260128 has 144 divisors (see below), whose sum is σ = 2113137936. Its totient is φ = 204664320.

The previous prime is 665260103. The next prime is 665260139. The reversal of 665260128 is 821062566.

665260128 is a `hidden beast` number, since 6 + 6 + 526 + 0 + 128 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 665260092 and 665260101.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 97798 + ... + 104378.

It is an arithmetic number, because the mean of its divisors is an integer number (14674569).

Almost surely, 2^665260128 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 665260128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1056568968).

665260128 is an abundant number, since it is smaller than the sum of its proper divisors (1447877808).

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

665260128 is a wasteful number, since it uses less digits than its factorization.

665260128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6619 (or 6599 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 36.

The square root of 665260128 is about 25792.6370889058. The cubic root of 665260128 is about 872.9656698159.

The spelling of 665260128 in words is "six hundred sixty-five million, two hundred sixty thousand, one hundred twenty-eight".