644022473 has 2 divisors, whose sum is σ = 644022474. Its totient is φ = 644022472.

The previous prime is 644022433. The next prime is 644022541. The reversal of 644022473 is 374220446.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 643738384 + 284089 = 25372^2 + 533^2 .

It is a cyclic number.

It is not a de Polignac number, because 644022473 - 2⁶ = 644022409 is a prime.

It is not a weakly prime, because it can be changed into another prime (644022403) 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 as a sum of consecutive naturals, namely, 322011236 + 322011237.

It is an arithmetic number, because the mean of its divisors is an integer number (322011237).

Almost surely, 2^644022473 is an apocalyptic number.

It is an amenable number.

644022473 is a deficient number, since it is larger than the sum of its proper divisors (1).

644022473 is an equidigital number, since it uses as much as digits as its factorization.

644022473 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32256, while the sum is 32.

The square root of 644022473 is about 25377.5978571653. The cubic root of 644022473 is about 863.5755557163.

The spelling of 644022473 in words is "six hundred forty-four million, twenty-two thousand, four hundred seventy-three".