21258320905 has 16 divisors (see below), whose sum is σ = 28432183680. Its totient is φ = 15163828992.

The previous prime is 21258320893. The next prime is 21258320933. The reversal of 21258320905 is 50902385212.

It is a cyclic number.

It is not a de Polignac number, because 21258320905 - 2⁷ = 21258320777 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6579909 + ... + 6583138.

It is an arithmetic number, because the mean of its divisors is an integer number (1777011480).

Almost surely, 2^21258320905 is an apocalyptic number.

It is an amenable number.

21258320905 is a deficient number, since it is larger than the sum of its proper divisors (7173862775).

21258320905 is a wasteful number, since it uses less digits than its factorization.

21258320905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13163088.

The product of its (nonzero) digits is 43200, while the sum is 37.

The spelling of 21258320905 in words is "twenty-one billion, two hundred fifty-eight million, three hundred twenty thousand, nine hundred five".