646106021 has 8 divisors (see below), whose sum is σ = 706152288. Its totient is φ = 586278000.

The previous prime is 646106011. The next prime is 646106033. The reversal of 646106021 is 120601646.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 646106021 - 2¹⁰ = 646104997 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 (646106011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48335 + ... + 60236.

It is an arithmetic number, because the mean of its divisors is an integer number (88269036).

Almost surely, 2^646106021 is an apocalyptic number.

It is an amenable number.

646106021 is a deficient number, since it is larger than the sum of its proper divisors (60046267).

646106021 is a wasteful number, since it uses less digits than its factorization.

646106021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109123.

The product of its (nonzero) digits is 1728, while the sum is 26.

The square root of 646106021 is about 25418.6156389368. The cubic root of 646106021 is about 864.5058360015.

Adding to 646106021 its reverse (120601646), we get a palindrome (766707667).

The spelling of 646106021 in words is "six hundred forty-six million, one hundred six thousand, twenty-one".