21163430789 has 4 divisors (see below), whose sum is σ = 21317908524. Its totient is φ = 21008953056.

The previous prime is 21163430779. The next prime is 21163430807. The reversal of 21163430789 is 98703436112.

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 6028280164 + 15135150625 = 77642^2 + 123025^2 .

It is a cyclic number.

It is not a de Polignac number, because 21163430789 - 2¹² = 21163426693 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 (21163430779) 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 3 ways as a sum of consecutive naturals, for example, 77238662 + ... + 77238935.

It is an arithmetic number, because the mean of its divisors is an integer number (5329477131).

Almost surely, 2^21163430789 is an apocalyptic number.

It is an amenable number.

21163430789 is a deficient number, since it is larger than the sum of its proper divisors (154477735).

21163430789 is a wasteful number, since it uses less digits than its factorization.

21163430789 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 154477734.

The product of its (nonzero) digits is 217728, while the sum is 44.

The spelling of 21163430789 in words is "twenty-one billion, one hundred sixty-three million, four hundred thirty thousand, seven hundred eighty-nine".