1944564989 has 2 divisors, whose sum is σ = 1944564990. Its totient is φ = 1944564988.

The previous prime is 1944564977. The next prime is 1944564991. The reversal of 1944564989 is 9894654491.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1897299364 + 47265625 = 43558^2 + 6875^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1944564989 is a prime.

Together with 1944564991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1944564959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 972282494 + 972282495.

It is an arithmetic number, because the mean of its divisors is an integer number (972282495).

Almost surely, 2^1944564989 is an apocalyptic number.

It is an amenable number.

1944564989 is a deficient number, since it is larger than the sum of its proper divisors (1).

1944564989 is an equidigital number, since it uses as much as digits as its factorization.

1944564989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11197440, while the sum is 59.

The square root of 1944564989 is about 44097.2220100087. Note that the first 3 decimals coincide. The cubic root of 1944564989 is about 1248.1711899880.

The spelling of 1944564989 in words is "one billion, nine hundred forty-four million, five hundred sixty-four thousand, nine hundred eighty-nine".