644422573 has 4 divisors (see below), whose sum is σ = 644473440. Its totient is φ = 644371708.

The previous prime is 644422531. The next prime is 644422577. The reversal of 644422573 is 375224446.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 644422573 - 2²¹ = 642325421 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 (644422577) 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, 10386 + ... + 37372.

It is an arithmetic number, because the mean of its divisors is an integer number (161118360).

Almost surely, 2^644422573 is an apocalyptic number.

It is an amenable number.

644422573 is a deficient number, since it is larger than the sum of its proper divisors (50867).

644422573 is a wasteful number, since it uses less digits than its factorization.

644422573 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 50866.

The product of its digits is 161280, while the sum is 37.

The square root of 644422573 is about 25385.4795700219. The cubic root of 644422573 is about 863.7543512647.

The spelling of 644422573 in words is "six hundred forty-four million, four hundred twenty-two thousand, five hundred seventy-three".