644146677 has 12 divisors (see below), whose sum is σ = 985165740. Its totient is φ = 404170368.

The previous prime is 644146663. The next prime is 644146687. The reversal of 644146677 is 776641446.

It can be written as a sum of positive squares in 2 ways, for example, as 341177841 + 302968836 = 18471^2 + 17406^2 .

It is not a de Polignac number, because 644146677 - 2¹² = 644142581 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644146627) by changing a digit.

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 in 11 ways as a sum of consecutive naturals, for example, 2104902 + ... + 2105207.

It is an arithmetic number, because the mean of its divisors is an integer number (82097145).

Almost surely, 2^644146677 is an apocalyptic number.

It is an amenable number.

644146677 is a deficient number, since it is larger than the sum of its proper divisors (341019063).

644146677 is a wasteful number, since it uses less digits than its factorization.

644146677 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4210132 (or 4210129 counting only the distinct ones).

The product of its digits is 677376, while the sum is 45.

The square root of 644146677 is about 25380.0448581164. The cubic root of 644146677 is about 863.6310675700.

The spelling of 644146677 in words is "six hundred forty-four million, one hundred forty-six thousand, six hundred seventy-seven".