646446021 has 16 divisors (see below), whose sum is σ = 929893440. Its totient is φ = 397100160.

The previous prime is 646445999. The next prime is 646446041. The reversal of 646446021 is 120644646.

It is not a de Polignac number, because 646446021 - 2⁹ = 646445509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646446041) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7626 + ... + 36756.

It is an arithmetic number, because the mean of its divisors is an integer number (58118340).

Almost surely, 2^646446021 is an apocalyptic number.

It is an amenable number.

646446021 is a deficient number, since it is larger than the sum of its proper divisors (283447419).

646446021 is a wasteful number, since it uses less digits than its factorization.

646446021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29716.

The product of its (nonzero) digits is 27648, while the sum is 33.

The square root of 646446021 is about 25425.3027710586. The cubic root of 646446021 is about 864.6574522127.

The spelling of 646446021 in words is "six hundred forty-six million, four hundred forty-six thousand, twenty-one".