665640450 has 48 divisors (see below), whose sum is σ = 1834212960. Its totient is φ = 177503760.

The previous prime is 665640421. The next prime is 665640527. The reversal of 665640450 is 54046566.

It is a happy number.

665640450 is a `hidden beast` number, since 6 + 6 + 5 + 640 + 4 + 5 + 0 = 666.

665640450 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 245184 + ... + 247883.

It is an arithmetic number, because the mean of its divisors is an integer number (38212770).

Almost surely, 2^665640450 is an apocalyptic number.

665640450 is an abundant number, since it is smaller than the sum of its proper divisors (1168572510).

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

665640450 is a wasteful number, since it uses less digits than its factorization.

665640450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 493088 (or 493077 counting only the distinct ones).

The product of its (nonzero) digits is 86400, while the sum is 36.

The square root of 665640450 is about 25800.0087209288. The cubic root of 665640450 is about 873.1319931267.

The spelling of 665640450 in words is "six hundred sixty-five million, six hundred forty thousand, four hundred fifty".