1644453947 has 2 divisors, whose sum is σ = 1644453948. Its totient is φ = 1644453946.

The previous prime is 1644453913. The next prime is 1644453997. The reversal of 1644453947 is 7493544461.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1644453947 - 2⁸ = 1644453691 is a prime.

It is not a weakly prime, because it can be changed into another prime (1644453997) 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, 822226973 + 822226974.

It is an arithmetic number, because the mean of its divisors is an integer number (822226974).

Almost surely, 2^1644453947 is an apocalyptic number.

1644453947 is a deficient number, since it is larger than the sum of its proper divisors (1).

1644453947 is an equidigital number, since it uses as much as digits as its factorization.

1644453947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1451520, while the sum is 47.

The square root of 1644453947 is about 40551.8673676071. The cubic root of 1644453947 is about 1180.3403085783.

The spelling of 1644453947 in words is "one billion, six hundred forty-four million, four hundred fifty-three thousand, nine hundred forty-seven".