1781344989 has 6 divisors (see below), whose sum is σ = 2573053886. Its totient is φ = 1187563320.

The previous prime is 1781344931. The next prime is 1781345023. The reversal of 1781344989 is 9894431871.

1781344989 is a `hidden beast` number, since 17 + 8 + 134 + 498 + 9 = 666.

It can be written as a sum of positive squares in only one way, i.e., 1604002500 + 177342489 = 40050^2 + 13317^2 .

It is a de Polignac number, because none of the positive numbers 2^k-1781344989 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1781344889) 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 in 5 ways as a sum of consecutive naturals, for example, 98963602 + ... + 98963619.

Almost surely, 2^1781344989 is an apocalyptic number.

It is an amenable number.

1781344989 is a deficient number, since it is larger than the sum of its proper divisors (791708897).

1781344989 is a wasteful number, since it uses less digits than its factorization.

1781344989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197927227 (or 197927224 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 54.

The square root of 1781344989 is about 42205.9828578840. The cubic root of 1781344989 is about 1212.2234438376.

The spelling of 1781344989 in words is "one billion, seven hundred eighty-one million, three hundred forty-four thousand, nine hundred eighty-nine".