665812224 has 432 divisors, whose sum is σ = 2499893760. Its totient is φ = 171694080.

The previous prime is 665812223. The next prime is 665812249. The reversal of 665812224 is 422218566.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (432).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665812223) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4789947 + ... + 4790085.

Almost surely, 2^665812224 is an apocalyptic number.

665812224 is a gapful number since it is divisible by the number (64) 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 665812224, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1249946880).

665812224 is an abundant number, since it is smaller than the sum of its proper divisors (1834081536).

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

665812224 is a wasteful number, since it uses less digits than its factorization.

665812224 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 162 counting only the distinct ones).

The product of its digits is 46080, while the sum is 36.

The square root of 665812224 is about 25803.3374585537. The cubic root of 665812224 is about 873.2070929675.

The spelling of 665812224 in words is "six hundred sixty-five million, eight hundred twelve thousand, two hundred twenty-four".