644135434 has 4 divisors (see below), whose sum is σ = 966203154. Its totient is φ = 322067716.

The previous prime is 644135411. The next prime is 644135449. The reversal of 644135434 is 434531446.

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

It can be written as a sum of positive squares in only one way, i.e., 622652209 + 21483225 = 24953^2 + 4635^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 644135434.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 161033857 + ... + 161033860.

Almost surely, 2^644135434 is an apocalyptic number.

644135434 is a deficient number, since it is larger than the sum of its proper divisors (322067720).

644135434 is a wasteful number, since it uses less digits than its factorization.

644135434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322067719.

The product of its digits is 69120, while the sum is 34.

The square root of 644135434 is about 25379.8233642396. The cubic root of 644135434 is about 863.6260429066.

The spelling of 644135434 in words is "six hundred forty-four million, one hundred thirty-five thousand, four hundred thirty-four".