644134805 has 32 divisors (see below), whose sum is σ = 828303840. Its totient is φ = 479969280.

The previous prime is 644134787. The next prime is 644134889. The reversal of 644134805 is 508431446.

It can be written as a sum of positive squares in 16 ways, for example, as 482285521 + 161849284 = 21961^2 + 12722^2 .

It is a de Polignac number, because none of the positive numbers 2^k-644134805 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 576107 + ... + 577223.

It is an arithmetic number, because the mean of its divisors is an integer number (25884495).

Almost surely, 2^644134805 is an apocalyptic number.

It is an amenable number.

644134805 is a deficient number, since it is larger than the sum of its proper divisors (184169035).

644134805 is a wasteful number, since it uses less digits than its factorization.

644134805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1289.

The product of its (nonzero) digits is 46080, while the sum is 35.

The square root of 644134805 is about 25379.8109725033. The cubic root of 644134805 is about 863.6257617955.

The spelling of 644134805 in words is "six hundred forty-four million, one hundred thirty-four thousand, eight hundred five".