646639213 has 8 divisors (see below), whose sum is σ = 707066496. Its totient is φ = 586485600.

The previous prime is 646639211. The next prime is 646639219. The reversal of 646639213 is 312936646.

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 646639213 - 2¹ = 646639211 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 (646639211) 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, 63456 + ... + 72937.

It is an arithmetic number, because the mean of its divisors is an integer number (88383312).

Almost surely, 2^646639213 is an apocalyptic number.

It is an amenable number.

646639213 is a deficient number, since it is larger than the sum of its proper divisors (60427283).

646639213 is a wasteful number, since it uses less digits than its factorization.

646639213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136835.

The product of its digits is 139968, while the sum is 40.

The square root of 646639213 is about 25429.1016947119. The cubic root of 646639213 is about 864.7435786431.

The spelling of 646639213 in words is "six hundred forty-six million, six hundred thirty-nine thousand, two hundred thirteen".