21364803605 has 4 divisors (see below), whose sum is σ = 25637764332. Its totient is φ = 17091842880.

The previous prime is 21364803599. The next prime is 21364803637. The reversal of 21364803605 is 50630846312.

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 14933084401 + 6431719204 = 122201^2 + 80198^2 .

It is not a de Polignac number, because 21364803605 - 2⁴ = 21364803589 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2136480356 + ... + 2136480365.

It is an arithmetic number, because the mean of its divisors is an integer number (6409441083).

Almost surely, 2^21364803605 is an apocalyptic number.

It is an amenable number.

21364803605 is a deficient number, since it is larger than the sum of its proper divisors (4272960727).

21364803605 is an equidigital number, since it uses as much as digits as its factorization.

21364803605 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4272960726.

The product of its (nonzero) digits is 103680, while the sum is 38.

The spelling of 21364803605 in words is "twenty-one billion, three hundred sixty-four million, eight hundred three thousand, six hundred five".