644333941 has 4 divisors (see below), whose sum is σ = 647572000. Its totient is φ = 641095884.

The previous prime is 644333917. The next prime is 644333953. The reversal of 644333941 is 149333446.

It is a happy number.

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, and also an emirpimes, since its reverse is a distinct semiprime: 149333446 = 2 ⋅74666723.

It is a cyclic number.

It is not a de Polignac number, because 644333941 - 2¹⁷ = 644202869 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 644333941.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644333971) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1618731 + ... + 1619128.

It is an arithmetic number, because the mean of its divisors is an integer number (161893000).

Almost surely, 2^644333941 is an apocalyptic number.

It is an amenable number.

644333941 is a deficient number, since it is larger than the sum of its proper divisors (3238059).

644333941 is a wasteful number, since it uses less digits than its factorization.

644333941 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3238058.

The product of its digits is 93312, while the sum is 37.

The square root of 644333941 is about 25383.7337876050. The cubic root of 644333941 is about 863.7147500315.

The spelling of 644333941 in words is "six hundred forty-four million, three hundred thirty-three thousand, nine hundred forty-one".