665306400 has 432 divisors, whose sum is σ = 2493590400. Its totient is φ = 153753600.

The previous prime is 665306393. The next prime is 665306401. The reversal of 665306400 is 4603566.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665306401) by changing a digit.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 8421561 + ... + 8421639.

It is an arithmetic number, because the mean of its divisors is an integer number (5772200).

Almost surely, 2^665306400 is an apocalyptic number.

665306400 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665306400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1246795200).

665306400 is an abundant number, since it is smaller than the sum of its proper divisors (1828284000).

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

665306400 is a wasteful number, since it uses less digits than its factorization.

665306400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153 (or 129 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 30.

The square root of 665306400 is about 25793.5340734844. The cubic root of 665306400 is about 872.9859089822.

Adding to 665306400 its reverse (4603566), we get a palindrome (669909966).

The spelling of 665306400 in words is "six hundred sixty-five million, three hundred six thousand, four hundred".