644089069 has 4 divisors (see below), whose sum is σ = 693634396. Its totient is φ = 594543744.

The previous prime is 644089003. The next prime is 644089073. The reversal of 644089069 is 960980446.

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 405015625 + 239073444 = 20125^2 + 15462^2 .

It is a cyclic number.

It is not a de Polignac number, because 644089069 - 2¹⁷ = 643957997 is a prime.

It is a super-2 number, since 2×644089069² = 829701457610573522, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644089099) by changing a digit.

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 in 3 ways as a sum of consecutive naturals, for example, 24772644 + ... + 24772669.

It is an arithmetic number, because the mean of its divisors is an integer number (173408599).

Almost surely, 2^644089069 is an apocalyptic number.

It is an amenable number.

644089069 is a deficient number, since it is larger than the sum of its proper divisors (49545327).

644089069 is a wasteful number, since it uses less digits than its factorization.

644089069 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49545326.

The product of its (nonzero) digits is 373248, while the sum is 46.

The square root of 644089069 is about 25378.9099253691. The cubic root of 644089069 is about 863.6053210832.

The spelling of 644089069 in words is "six hundred forty-four million, eighty-nine thousand, sixty-nine".