646065221 has 4 divisors (see below), whose sum is σ = 646190412. Its totient is φ = 645940032.

The previous prime is 646065197. The next prime is 646065253. The reversal of 646065221 is 122560646.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 634334596 + 11730625 = 25186^2 + 3425^2 .

It is a cyclic number.

It is not a de Polignac number, because 646065221 - 2⁶ = 646065157 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 (646065421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 54506 + ... + 65291.

It is an arithmetic number, because the mean of its divisors is an integer number (161547603).

Almost surely, 2^646065221 is an apocalyptic number.

It is an amenable number.

646065221 is a deficient number, since it is larger than the sum of its proper divisors (125191).

646065221 is a wasteful number, since it uses less digits than its factorization.

646065221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125190.

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 646065221 is about 25417.8130648567. The cubic root of 646065221 is about 864.4876384821.

The spelling of 646065221 in words is "six hundred forty-six million, sixty-five thousand, two hundred twenty-one".