644714461 has 4 divisors (see below), whose sum is σ = 646443292. Its totient is φ = 642985632.

The previous prime is 644714431. The next prime is 644714467. The reversal of 644714461 is 164417446.

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

It can be written as a sum of positive squares in 2 ways, for example, as 474411961 + 170302500 = 21781^2 + 13050^2 .

It is a cyclic number.

It is not a de Polignac number, because 644714461 - 2¹⁵ = 644681693 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 644714461.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644714467) 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 3 ways as a sum of consecutive naturals, for example, 863856 + ... + 864601.

It is an arithmetic number, because the mean of its divisors is an integer number (161610823).

Almost surely, 2^644714461 is an apocalyptic number.

It is an amenable number.

644714461 is a deficient number, since it is larger than the sum of its proper divisors (1728831).

644714461 is a wasteful number, since it uses less digits than its factorization.

644714461 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1728830.

The product of its digits is 64512, while the sum is 37.

The square root of 644714461 is about 25391.2280325312. The cubic root of 644714461 is about 863.8847426594.

The spelling of 644714461 in words is "six hundred forty-four million, seven hundred fourteen thousand, four hundred sixty-one".