665029440 has 140 divisors (see below), whose sum is σ = 2365718916. Its totient is φ = 177334272.

The previous prime is 665029433. The next prime is 665029447. The reversal of 665029440 is 44920566.

665029440 is a `hidden beast` number, since 66 + 502 + 94 + 4 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (665029433) and next prime (665029447).

It can be written as a sum of positive squares in 2 ways, for example, as 219988224 + 445041216 = 14832^2 + 21096^2 .

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 = 665029395 and 665029404.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665029447) 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 19 ways as a sum of consecutive naturals, for example, 13092 + ... + 38748.

Almost surely, 2^665029440 is an apocalyptic number.

665029440 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 665029440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1182859458).

665029440 is an abundant number, since it is smaller than the sum of its proper divisors (1700689476).

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

665029440 is a wasteful number, since it uses less digits than its factorization.

665029440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25686 (or 25667 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The square root of 665029440 is about 25788.1647272542. The cubic root of 665029440 is about 872.8647539096.

The spelling of 665029440 in words is "six hundred sixty-five million, twenty-nine thousand, four hundred forty".