644928958 has 4 divisors (see below), whose sum is σ = 967393440. Its totient is φ = 322464478.

The previous prime is 644928937. The next prime is 644928961. The reversal of 644928958 is 859829446.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 644928899 and 644928908.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161232238 + ... + 161232241.

It is an arithmetic number, because the mean of its divisors is an integer number (241848360).

Almost surely, 2^644928958 is an apocalyptic number.

644928958 is a deficient number, since it is larger than the sum of its proper divisors (322464482).

644928958 is a wasteful number, since it uses less digits than its factorization.

644928958 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322464481.

The product of its digits is 4976640, while the sum is 55.

The square root of 644928958 is about 25395.4515218769. The cubic root of 644928958 is about 863.9805370773.

The spelling of 644928958 in words is "six hundred forty-four million, nine hundred twenty-eight thousand, nine hundred fifty-eight".