644453343 has 24 divisors (see below), whose sum is σ = 987058800. Its totient is φ = 404037504.

The previous prime is 644453339. The next prime is 644453347. The reversal of 644453343 is 343354446.

644453343 is a `hidden beast` number, since 644 + 4 + 5 + 3 + 3 + 4 + 3 = 666.

It is an interprime number because it is at equal distance from previous prime (644453339) and next prime (644453347).

It is not a de Polignac number, because 644453343 - 2² = 644453339 is a prime.

It is a super-2 number, since 2×644453343² = 830640222607751298, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 644453298 and 644453307.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644453347) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9673 + ... + 37181.

It is an arithmetic number, because the mean of its divisors is an integer number (41127450).

Almost surely, 2^644453343 is an apocalyptic number.

644453343 is a deficient number, since it is larger than the sum of its proper divisors (342605457).

644453343 is a wasteful number, since it uses less digits than its factorization.

644453343 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27671 (or 27668 counting only the distinct ones).

The product of its digits is 207360, while the sum is 36.

The square root of 644453343 is about 25386.0856179128. The cubic root of 644453343 is about 863.7680986097.

The spelling of 644453343 in words is "six hundred forty-four million, four hundred fifty-three thousand, three hundred forty-three".