644036417 has 4 divisors (see below), whose sum is σ = 645041796. Its totient is φ = 643031040.

The previous prime is 644036411. The next prime is 644036461. The reversal of 644036417 is 714630446.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 714630446 = 2 ⋅357315223.

It can be written as a sum of positive squares in 2 ways, for example, as 568154896 + 75881521 = 23836^2 + 8711^2 .

It is a cyclic number.

It is not a de Polignac number, because 644036417 - 2¹² = 644032321 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644036411) 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, 501728 + ... + 503009.

It is an arithmetic number, because the mean of its divisors is an integer number (161260449).

Almost surely, 2^644036417 is an apocalyptic number.

It is an amenable number.

644036417 is a deficient number, since it is larger than the sum of its proper divisors (1005379).

644036417 is a wasteful number, since it uses less digits than its factorization.

644036417 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1005378.

The product of its (nonzero) digits is 48384, while the sum is 35.

The square root of 644036417 is about 25377.8725861724. The cubic root of 644036417 is about 863.5817882166.

The spelling of 644036417 in words is "six hundred forty-four million, thirty-six thousand, four hundred seventeen".