665719760 has 80 divisors (see below), whose sum is σ = 1582773696. Its totient is φ = 260342784.

The previous prime is 665719757. The next prime is 665719783. The reversal of 665719760 is 67917566.

665719760 = T₂₆₁ + T₂₆₂ + ... + T₁₅₈₈.

It is a happy number.

665719760 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 710012 + ... + 710948.

Almost surely, 2^665719760 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 665719760, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (791386848).

665719760 is an abundant number, since it is smaller than the sum of its proper divisors (917053936).

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

665719760 is a wasteful number, since it uses less digits than its factorization.

665719760 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1140 (or 1134 counting only the distinct ones).

The product of its (nonzero) digits is 476280, while the sum is 47.

The square root of 665719760 is about 25801.5456901326. The cubic root of 665719760 is about 873.1666691786.

The spelling of 665719760 in words is "six hundred sixty-five million, seven hundred nineteen thousand, seven hundred sixty".