1644442091 has 2 divisors, whose sum is σ = 1644442092. Its totient is φ = 1644442090.

The previous prime is 1644442069. The next prime is 1644442103. The reversal of 1644442091 is 1902444461.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1644442091 - 2¹⁸ = 1644179947 is a prime.

It is not a weakly prime, because it can be changed into another prime (1644442291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 822221045 + 822221046.

It is an arithmetic number, because the mean of its divisors is an integer number (822221046).

Almost surely, 2^1644442091 is an apocalyptic number.

1644442091 is a deficient number, since it is larger than the sum of its proper divisors (1).

1644442091 is an equidigital number, since it uses as much as digits as its factorization.

1644442091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 27648, while the sum is 35.

The square root of 1644442091 is about 40551.7211841865. The cubic root of 1644442091 is about 1180.3374719430.

The spelling of 1644442091 in words is "one billion, six hundred forty-four million, four hundred forty-two thousand, ninety-one".