665605494400 has 768 divisors, whose sum is σ = 2165084640000. Its totient is φ = 200202240000.

The previous prime is 665605494343. The next prime is 665605494403. The reversal of 665605494400 is 4494506566.

665605494400 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 (49).

It is not an unprimeable number, because it can be changed into a prime (665605494403) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 350133450 + ... + 350135350.

It is an arithmetic number, because the mean of its divisors is an integer number (2819120625).

Almost surely, 2^665605494400 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 665605494400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1082542320000).

665605494400 is an abundant number, since it is smaller than the sum of its proper divisors (1499479145600).

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

665605494400 is a wasteful number, since it uses less digits than its factorization.

665605494400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1986 (or 1955 counting only the distinct ones).

The product of its (nonzero) digits is 3110400, while the sum is 49.

The spelling of 665605494400 in words is "six hundred sixty-five billion, six hundred five million, four hundred ninety-four thousand, four hundred".