644609877 has 16 divisors (see below), whose sum is σ = 888107520. Its totient is φ = 415454400.

The previous prime is 644609873. The next prime is 644609879. The reversal of 644609877 is 778906446.

It is not a de Polignac number, because 644609877 - 2² = 644609873 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644609873) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 106899 + ... + 112767.

It is an arithmetic number, because the mean of its divisors is an integer number (55506720).

Almost surely, 2^644609877 is an apocalyptic number.

It is an amenable number.

644609877 is a deficient number, since it is larger than the sum of its proper divisors (243497643).

644609877 is a wasteful number, since it uses less digits than its factorization.

644609877 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7084.

The product of its (nonzero) digits is 2032128, while the sum is 51.

The square root of 644609877 is about 25389.1684976094. The cubic root of 644609877 is about 863.8380277113.

The spelling of 644609877 in words is "six hundred forty-four million, six hundred nine thousand, eight hundred seventy-seven".