665344400 has 120 divisors (see below), whose sum is σ = 1835340864. Its totient is φ = 227059200.

The previous prime is 665344369. The next prime is 665344409. The reversal of 665344400 is 4443566.

It is a super-2 number, since 2×665344400² = 885366341222720000, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (665344409) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 819995 + ... + 820805.

Almost surely, 2^665344400 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 665344400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (917670432).

665344400 is an abundant number, since it is smaller than the sum of its proper divisors (1169996464).

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

665344400 is a wasteful number, since it uses less digits than its factorization.

665344400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1129 (or 1118 counting only the distinct ones).

The product of its (nonzero) digits is 34560, while the sum is 32.

The square root of 665344400 is about 25794.2706816843. The cubic root of 665344400 is about 873.0025293108.

Adding to 665344400 its reverse (4443566), we get a palindrome (669787966).

The spelling of 665344400 in words is "six hundred sixty-five million, three hundred forty-four thousand, four hundred".