665422128 has 200 divisors, whose sum is σ = 2256001440. Its totient is φ = 185379840.

The previous prime is 665422111. The next prime is 665422129. The reversal of 665422128 is 821224566.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 665422092 and 665422101.

It is not an unprimeable number, because it can be changed into a prime (665422129) 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 39 ways as a sum of consecutive naturals, for example, 371058 + ... + 372846.

Almost surely, 2^665422128 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 665422128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1128000720).

665422128 is an abundant number, since it is smaller than the sum of its proper divisors (1590579312).

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

665422128 is a wasteful number, since it uses less digits than its factorization.

665422128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1857 (or 1842 counting only the distinct ones).

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

The square root of 665422128 is about 25795.7773288575. Note that the first 3 decimals coincide. The cubic root of 665422128 is about 873.0365237846.

It can be divided in two parts, 6654 and 22128, that added together give a palindrome (28782).

The spelling of 665422128 in words is "six hundred sixty-five million, four hundred twenty-two thousand, one hundred twenty-eight".