665500000000 has 360 divisors, whose sum is σ = 1826425594224. Its totient is φ = 242000000000.

The previous prime is 665499999977. The next prime is 665500000037. The reversal of 665500000000 is 5566.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is a nialpdrome in base 10.

It is a zygodrome in base 10.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 60499999995 + ... + 60500000005.

Almost surely, 2^665500000000 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 665500000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (913212797112).

665500000000 is an abundant number, since it is smaller than the sum of its proper divisors (1160925594224).

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

665500000000 is an frugal number, since it uses more digits than its factorization.

665500000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94 (or 18 counting only the distinct ones).

The product of its (nonzero) digits is 900, while the sum is 22.

Adding to 665500000000 its reverse (5566), we get a palindrome (665500005566).

The spelling of 665500000000 in words is "six hundred sixty-five billion, five hundred million", and thus it is an aban number.