21765143889 has 12 divisors (see below), whose sum is σ = 31443347572. Its totient is φ = 14507877600.

The previous prime is 21765143861. The next prime is 21765143893. The reversal of 21765143889 is 98834156712.

21765143889 is a `hidden beast` number, since 2 + 17 + 6 + 514 + 38 + 89 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 12032334864 + 9732809025 = 109692^2 + 98655^2 .

It is not a de Polignac number, because 21765143889 - 2⁷ = 21765143761 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21765143819) 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 11 ways as a sum of consecutive naturals, for example, 121582 + ... + 241479.

Almost surely, 2^21765143889 is an apocalyptic number.

It is an amenable number.

21765143889 is a deficient number, since it is larger than the sum of its proper divisors (9678203683).

21765143889 is a wasteful number, since it uses less digits than its factorization.

21765143889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 369728 (or 369725 counting only the distinct ones).

The product of its digits is 2903040, while the sum is 54.

The spelling of 21765143889 in words is "twenty-one billion, seven hundred sixty-five million, one hundred forty-three thousand, eight hundred eighty-nine".