644053513 has 8 divisors (see below), whose sum is σ = 654304160. Its totient is φ = 633821760.

The previous prime is 644053463. The next prime is 644053589. The reversal of 644053513 is 315350446.

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 644053513 - 2⁹ = 644053001 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644056513) 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, 74353 + ... + 82561.

It is an arithmetic number, because the mean of its divisors is an integer number (81788020).

Almost surely, 2^644053513 is an apocalyptic number.

It is an amenable number.

644053513 is a deficient number, since it is larger than the sum of its proper divisors (10250647).

644053513 is a wasteful number, since it uses less digits than its factorization.

644053513 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9447.

The product of its (nonzero) digits is 21600, while the sum is 31.

The square root of 644053513 is about 25378.2094128014. The cubic root of 644053513 is about 863.5894294323.

The spelling of 644053513 in words is "six hundred forty-four million, fifty-three thousand, five hundred thirteen".