665071398 has 40 divisors (see below), whose sum is σ = 1495850400. Its totient is φ = 220857840.

The previous prime is 665071397. The next prime is 665071417. The reversal of 665071398 is 893170566.

It is a happy number.

665071398 is a `hidden beast` number, since 6 + 6 + 507 + 139 + 8 = 666.

665071398 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665071397) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 36328 + ... + 51476.

It is an arithmetic number, because the mean of its divisors is an integer number (37396260).

Almost surely, 2^665071398 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665071398, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (747925200).

665071398 is an abundant number, since it is smaller than the sum of its proper divisors (830779002).

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

665071398 is a wasteful number, since it uses less digits than its factorization.

665071398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15434 (or 15425 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 45.

The square root of 665071398 is about 25788.9782271419. The cubic root of 665071398 is about 872.8831104348.

The spelling of 665071398 in words is "six hundred sixty-five million, seventy-one thousand, three hundred ninety-eight".