644443846 has 4 divisors (see below), whose sum is σ = 966665772. Its totient is φ = 322221922.

The previous prime is 644443823. The next prime is 644443867. The reversal of 644443846 is 648344446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 648344446 = 2 ⋅324172223.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161110960 + ... + 161110963.

It is an arithmetic number, because the mean of its divisors is an integer number (241666443).

Almost surely, 2^644443846 is an apocalyptic number.

644443846 is a deficient number, since it is larger than the sum of its proper divisors (322221926).

644443846 is a wasteful number, since it uses less digits than its factorization.

644443846 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 322221925.

The product of its digits is 884736, while the sum is 43.

The square root of 644443846 is about 25385.8985659362. The cubic root of 644443846 is about 863.7638556100.

The spelling of 644443846 in words is "six hundred forty-four million, four hundred forty-three thousand, eight hundred forty-six".