20843504989 has 4 divisors (see below), whose sum is σ = 20844593980. Its totient is φ = 20842416000.

The previous prime is 20843504953. The next prime is 20843505013. The reversal of 20843504989 is 98940534802.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5843379364 + 15000125625 = 76442^2 + 122475^2 .

It is a cyclic number.

It is not a de Polignac number, because 20843504989 - 2¹¹ = 20843502941 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 (20843504909) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 515262 + ... + 554239.

It is an arithmetic number, because the mean of its divisors is an integer number (5211148495).

Almost surely, 2^20843504989 is an apocalyptic number.

It is an amenable number.

20843504989 is a deficient number, since it is larger than the sum of its proper divisors (1088991).

20843504989 is a wasteful number, since it uses less digits than its factorization.

20843504989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1088990.

The product of its (nonzero) digits is 2488320, while the sum is 52.

The spelling of 20843504989 in words is "twenty billion, eight hundred forty-three million, five hundred four thousand, nine hundred eighty-nine".