644592616 has 8 divisors (see below), whose sum is σ = 1208611170. Its totient is φ = 322296304.

The previous prime is 644592607. The next prime is 644592631. The reversal of 644592616 is 616295446.

It can be written as a sum of positive squares in only one way, i.e., 390062500 + 254530116 = 19750^2 + 15954^2 .

It is a tau number, because it is divible by the number of its divisors (8).

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, 40287031 + ... + 40287046.

Almost surely, 2^644592616 is an apocalyptic number.

It is an amenable number.

644592616 is a deficient number, since it is larger than the sum of its proper divisors (564018554).

644592616 is a wasteful number, since it uses less digits than its factorization.

644592616 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80574083 (or 80574079 counting only the distinct ones).

The product of its digits is 311040, while the sum is 43.

The square root of 644592616 is about 25388.8285669111. The cubic root of 644592616 is about 863.8303171865.

The spelling of 644592616 in words is "six hundred forty-four million, five hundred ninety-two thousand, six hundred sixteen".