644273363 has 2 divisors, whose sum is σ = 644273364. Its totient is φ = 644273362.

The previous prime is 644273359. The next prime is 644273381. The reversal of 644273363 is 363372446.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 644273363 - 2² = 644273359 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (644273393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 322136681 + 322136682.

It is an arithmetic number, because the mean of its divisors is an integer number (322136682).

Almost surely, 2^644273363 is an apocalyptic number.

644273363 is a deficient number, since it is larger than the sum of its proper divisors (1).

644273363 is an equidigital number, since it uses as much as digits as its factorization.

644273363 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 38.

The square root of 644273363 is about 25382.5405150863. The cubic root of 644273363 is about 863.6876813804.

The spelling of 644273363 in words is "six hundred forty-four million, two hundred seventy-three thousand, three hundred sixty-three".