665909500 has 48 divisors (see below), whose sum is σ = 1460047680. Its totient is φ = 265320000.

The previous prime is 665909479. The next prime is 665909507. The reversal of 665909500 is 5909566.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665909507) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 132025 + ... + 136975.

It is an arithmetic number, because the mean of its divisors is an integer number (30417660).

Almost surely, 2^665909500 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 665909500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (730023840).

665909500 is an abundant number, since it is smaller than the sum of its proper divisors (794138180).

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

665909500 is a wasteful number, since it uses less digits than its factorization.

665909500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5239 (or 5227 counting only the distinct ones).

The product of its (nonzero) digits is 72900, while the sum is 40.

The square root of 665909500 is about 25805.2223396738. Note that the first 3 decimals coincide. The cubic root of 665909500 is about 873.2496164467.

The spelling of 665909500 in words is "six hundred sixty-five million, nine hundred nine thousand, five hundred".