665025398 has 16 divisors (see below), whose sum is σ = 1002516480. Its totient is φ = 330858216.

The previous prime is 665025391. The next prime is 665025409. The reversal of 665025398 is 893520566.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665025391) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 423611 + ... + 425177.

It is an arithmetic number, because the mean of its divisors is an integer number (62657280).

Almost surely, 2^665025398 is an apocalyptic number.

665025398 is a deficient number, since it is larger than the sum of its proper divisors (337491082).

665025398 is a wasteful number, since it uses less digits than its factorization.

665025398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2491.

The product of its (nonzero) digits is 388800, while the sum is 44.

The square root of 665025398 is about 25788.0863578514. The cubic root of 665025398 is about 872.8629855034.

The spelling of 665025398 in words is "six hundred sixty-five million, twenty-five thousand, three hundred ninety-eight".