646268021 has 4 divisors (see below), whose sum is σ = 738592032. Its totient is φ = 553944012.

The previous prime is 646268017. The next prime is 646268047. The reversal of 646268021 is 120862646.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 646268021 - 2² = 646268017 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 (646268081) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 46161995 + ... + 46162008.

It is an arithmetic number, because the mean of its divisors is an integer number (184648008).

Almost surely, 2^646268021 is an apocalyptic number.

It is an amenable number.

646268021 is a deficient number, since it is larger than the sum of its proper divisors (92324011).

646268021 is an equidigital number, since it uses as much as digits as its factorization.

646268021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92324010.

The product of its (nonzero) digits is 27648, while the sum is 35.

The square root of 646268021 is about 25421.8020801044. The cubic root of 646268021 is about 864.5780832992.

The spelling of 646268021 in words is "six hundred forty-six million, two hundred sixty-eight thousand, twenty-one".