644557001041 has 8 divisors (see below), whose sum is σ = 650284593480. Its totient is φ = 638829821952.

The previous prime is 644557001027. The next prime is 644557001171. The reversal of 644557001041 is 140100755446.

It can be written as a sum of positive squares in 4 ways, for example, as 7120828225 + 637436172816 = 84385^2 + 798396^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 644557001041 - 2¹⁷ = 644556869969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644557007041) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 3623265 + ... + 3796993.

It is an arithmetic number, because the mean of its divisors is an integer number (81285574185).

Almost surely, 2^644557001041 is an apocalyptic number.

It is an amenable number.

644557001041 is a deficient number, since it is larger than the sum of its proper divisors (5727592439).

644557001041 is a wasteful number, since it uses less digits than its factorization.

644557001041 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206675.

The product of its (nonzero) digits is 67200, while the sum is 37.

Adding to 644557001041 its reverse (140100755446), we get a palindrome (784657756487).

The spelling of 644557001041 in words is "six hundred forty-four billion, five hundred fifty-seven million, one thousand, forty-one".