646870393 has 8 divisors (see below), whose sum is σ = 696832136. Its totient is φ = 596937600.

The previous prime is 646870381. The next prime is 646870481. The reversal of 646870393 is 393078646.

It can be written as a sum of positive squares in 4 ways, for example, as 208889209 + 437981184 = 14453^2 + 20928^2 .

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 646870393 - 2⁵ = 646870361 is a prime.

It is not an unprimeable number, because it can be changed into a prime (646870313) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 68923 + ... + 77743.

It is an arithmetic number, because the mean of its divisors is an integer number (87104017).

Almost surely, 2^646870393 is an apocalyptic number.

It is an amenable number.

646870393 is a deficient number, since it is larger than the sum of its proper divisors (49961743).

646870393 is a wasteful number, since it uses less digits than its factorization.

646870393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14475.

The product of its (nonzero) digits is 653184, while the sum is 46.

The square root of 646870393 is about 25433.6468678796. The cubic root of 646870393 is about 864.8466178638.

The spelling of 646870393 in words is "six hundred forty-six million, eight hundred seventy thousand, three hundred ninety-three".