1561944443 has 2 divisors, whose sum is σ = 1561944444. Its totient is φ = 1561944442.

The previous prime is 1561944359. The next prime is 1561944451. The reversal of 1561944443 is 3444491651.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1561944443 - 2⁸ = 1561944187 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1561944443.

It is not a weakly prime, because it can be changed into another prime (1561944463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 780972221 + 780972222.

It is an arithmetic number, because the mean of its divisors is an integer number (780972222).

Almost surely, 2^1561944443 is an apocalyptic number.

1561944443 is a deficient number, since it is larger than the sum of its proper divisors (1).

1561944443 is an equidigital number, since it uses as much as digits as its factorization.

1561944443 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 207360, while the sum is 41.

The square root of 1561944443 is about 39521.4428253828. The cubic root of 1561944443 is about 1160.2596631846.

The spelling of 1561944443 in words is "one billion, five hundred sixty-one million, nine hundred forty-four thousand, four hundred forty-three".