644001045 has 8 divisors (see below), whose sum is σ = 1030401696. Its totient is φ = 343467216.

The previous prime is 644001041. The next prime is 644001079. The reversal of 644001045 is 540100446.

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

It is not a de Polignac number, because 644001045 - 2² = 644001041 is a prime.

It is a super-2 number, since 2×644001045² = 829474691922184050, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644001041) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 21466687 + ... + 21466716.

It is an arithmetic number, because the mean of its divisors is an integer number (128800212).

Almost surely, 2^644001045 is an apocalyptic number.

It is an amenable number.

644001045 is a deficient number, since it is larger than the sum of its proper divisors (386400651).

644001045 is a wasteful number, since it uses less digits than its factorization.

644001045 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 42933411.

The product of its (nonzero) digits is 1920, while the sum is 24.

The square root of 644001045 is about 25377.1756702751. The cubic root of 644001045 is about 863.5659779438.

The spelling of 644001045 in words is "six hundred forty-four million, one thousand, forty-five".