644356653446 has 16 divisors (see below), whose sum is σ = 1064841421968. Its totient is φ = 289989492000.

The previous prime is 644356653443. The next prime is 644356653497.

644356653446 is nontrivially palindromic in base 10.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 644356653391 and 644356653400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644356653443) 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, 144992525 + ... + 144996968.

It is an arithmetic number, because the mean of its divisors is an integer number (66552588873).

Almost surely, 2^644356653446 is an apocalyptic number.

644356653446 is a deficient number, since it is larger than the sum of its proper divisors (420484768522).

644356653446 is a wasteful number, since it uses less digits than its factorization.

644356653446 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 289989607.

The product of its digits is 74649600, while the sum is 56.

The spelling of 644356653446 in words is "six hundred forty-four billion, three hundred fifty-six million, six hundred fifty-three thousand, four hundred forty-six".