644003446 has 4 divisors (see below), whose sum is σ = 966005172. Its totient is φ = 322001722.

The previous prime is 644003429. The next prime is 644003449. The reversal of 644003446 is 644300446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 644300446 = 2 ⋅322150223.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644003449) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161000860 + ... + 161000863.

It is an arithmetic number, because the mean of its divisors is an integer number (241501293).

Almost surely, 2^644003446 is an apocalyptic number.

644003446 is a deficient number, since it is larger than the sum of its proper divisors (322001726).

644003446 is a wasteful number, since it uses less digits than its factorization.

644003446 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322001725.

The product of its (nonzero) digits is 27648, while the sum is 31.

The square root of 644003446 is about 25377.2229765197. Note that the first 3 decimals coincide. The cubic root of 644003446 is about 863.5670511405.

The spelling of 644003446 in words is "six hundred forty-four million, three thousand, four hundred forty-six".