644100053 has 4 divisors (see below), whose sum is σ = 659079168. Its totient is φ = 629120940.

The previous prime is 644100049. The next prime is 644100071. The reversal of 644100053 is 350001446.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 644100053 - 2² = 644100049 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644100553) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7489493 + ... + 7489578.

It is an arithmetic number, because the mean of its divisors is an integer number (164769792).

Almost surely, 2^644100053 is an apocalyptic number.

It is an amenable number.

644100053 is a deficient number, since it is larger than the sum of its proper divisors (14979115).

644100053 is a wasteful number, since it uses less digits than its factorization.

644100053 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14979114.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 644100053 is about 25379.1263245999. The cubic root of 644100053 is about 863.6102302318.

Adding to 644100053 its reverse (350001446), we get a palindrome (994101499).

The spelling of 644100053 in words is "six hundred forty-four million, one hundred thousand, fifty-three".