644676473 has 16 divisors (see below), whose sum is σ = 741933696. Its totient is φ = 548726400.

The previous prime is 644676469. The next prime is 644676481. The reversal of 644676473 is 374676446.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 644676473 - 2² = 644676469 is a prime.

It is not an unprimeable number, because it can be changed into a prime (644676433) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1072373 + ... + 1072973.

It is an arithmetic number, because the mean of its divisors is an integer number (46370856).

Almost surely, 2^644676473 is an apocalyptic number.

It is an amenable number.

644676473 is a deficient number, since it is larger than the sum of its proper divisors (97257223).

644676473 is a wasteful number, since it uses less digits than its factorization.

644676473 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1424.

The product of its digits is 2032128, while the sum is 47.

The square root of 644676473 is about 25390.4799678935. The cubic root of 644676473 is about 863.8677749938.

The spelling of 644676473 in words is "six hundred forty-four million, six hundred seventy-six thousand, four hundred seventy-three".