646405351 has 8 divisors (see below), whose sum is σ = 651039984. Its totient is φ = 641779200.

The previous prime is 646405343. The next prime is 646405373. The reversal of 646405351 is 153504646.

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 646405351 - 2³ = 646405343 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 (646405051) 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, 259725 + ... + 262201.

It is an arithmetic number, because the mean of its divisors is an integer number (81379998).

Almost surely, 2^646405351 is an apocalyptic number.

646405351 is a deficient number, since it is larger than the sum of its proper divisors (4634633).

646405351 is a wasteful number, since it uses less digits than its factorization.

646405351 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4241.

The product of its (nonzero) digits is 43200, while the sum is 34.

The square root of 646405351 is about 25424.5029646599. The cubic root of 646405351 is about 864.6393190379.

Adding to 646405351 its reverse (153504646), we get a palindrome (799909997).

The spelling of 646405351 in words is "six hundred forty-six million, four hundred five thousand, three hundred fifty-one".