663309391 has 8 divisors (see below), whose sum is σ = 670970144. Its totient is φ = 655672320.

The previous prime is 663309343. The next prime is 663309401. The reversal of 663309391 is 193903366.

It is a happy number.

663309391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 663309391 - 2¹⁵ = 663276623 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (663309301) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53851 + ... + 65011.

It is an arithmetic number, because the mean of its divisors is an integer number (83871268).

Almost surely, 2^663309391 is an apocalyptic number.

663309391 is a deficient number, since it is larger than the sum of its proper divisors (7660753).

663309391 is a wasteful number, since it uses less digits than its factorization.

663309391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11841.

The product of its (nonzero) digits is 78732, while the sum is 40.

The square root of 663309391 is about 25754.7935538222. The cubic root of 663309391 is about 872.1115710108. Note that the first 3 decimals are identical.

The spelling of 663309391 in words is "six hundred sixty-three million, three hundred nine thousand, three hundred ninety-one".