21204616073 has 4 divisors (see below), whose sum is σ = 21205669908. Its totient is φ = 21203562240.

The previous prime is 21204616031. The next prime is 21204616091. The reversal of 21204616073 is 37061640212.

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 10593143929 + 10611472144 = 102923^2 + 103012^2 .

It is a cyclic number.

It is not a de Polignac number, because 21204616073 - 2³⁰ = 20130874249 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21204615073) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 496136 + ... + 537177.

It is an arithmetic number, because the mean of its divisors is an integer number (5301417477).

Almost surely, 2^21204616073 is an apocalyptic number.

It is an amenable number.

21204616073 is a deficient number, since it is larger than the sum of its proper divisors (1053835).

21204616073 is a wasteful number, since it uses less digits than its factorization.

21204616073 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1053834.

The product of its (nonzero) digits is 12096, while the sum is 32.

The spelling of 21204616073 in words is "twenty-one billion, two hundred four million, six hundred sixteen thousand, seventy-three".