644457473 has 8 divisors (see below), whose sum is σ = 703299360. Its totient is φ = 585658080.

The previous prime is 644457461. The next prime is 644457479. The reversal of 644457473 is 374754446.

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 644457473 - 2¹⁸ = 644195329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (644457479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 26861 + ... + 44837.

It is an arithmetic number, because the mean of its divisors is an integer number (87912420).

Almost surely, 2^644457473 is an apocalyptic number.

It is an amenable number.

644457473 is a deficient number, since it is larger than the sum of its proper divisors (58841887).

644457473 is a wasteful number, since it uses less digits than its factorization.

644457473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21247.

The product of its digits is 1128960, while the sum is 44.

The square root of 644457473 is about 25386.1669615561. The cubic root of 644457473 is about 863.7699437676.

The spelling of 644457473 in words is "six hundred forty-four million, four hundred fifty-seven thousand, four hundred seventy-three".