644712273 has 12 divisors (see below), whose sum is σ = 938050308. Its totient is φ = 426670080.

The previous prime is 644712269. The next prime is 644712281. The reversal of 644712273 is 372217446.

644712273 is a `hidden beast` number, since 644 + 7 + 1 + 2 + 2 + 7 + 3 = 666.

644712273 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 343620369 + 301091904 = 18537^2 + 17352^2 .

It is not a de Polignac number, because 644712273 - 2² = 644712269 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644712283) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 260208 + ... + 262673.

It is an arithmetic number, because the mean of its divisors is an integer number (78170859).

Almost surely, 2^644712273 is an apocalyptic number.

It is an amenable number.

644712273 is a deficient number, since it is larger than the sum of its proper divisors (293338035).

644712273 is a wasteful number, since it uses less digits than its factorization.

644712273 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 523024 (or 523021 counting only the distinct ones).

The product of its digits is 56448, while the sum is 36.

The square root of 644712273 is about 25391.1849467487. The cubic root of 644712273 is about 863.8837653885.

The spelling of 644712273 in words is "six hundred forty-four million, seven hundred twelve thousand, two hundred seventy-three".