21355066205 has 32 divisors (see below), whose sum is σ = 29701582848. Its totient is φ = 14567296000.

The previous prime is 21355066133. The next prime is 21355066219. The reversal of 21355066205 is 50266055312.

It is not a de Polignac number, because 21355066205 - 2¹⁸ = 21354804061 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 31 ways as a sum of consecutive naturals, for example, 234980 + ... + 312930.

It is an arithmetic number, because the mean of its divisors is an integer number (928174464).

Almost surely, 2^21355066205 is an apocalyptic number.

It is an amenable number.

21355066205 is a deficient number, since it is larger than the sum of its proper divisors (8346516643).

21355066205 is a wasteful number, since it uses less digits than its factorization.

21355066205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78277.

The product of its (nonzero) digits is 54000, while the sum is 35.

The spelling of 21355066205 in words is "twenty-one billion, three hundred fifty-five million, sixty-six thousand, two hundred five".