21373205 has 16 divisors (see below), whose sum is σ = 29420544. Its totient is φ = 14601600.

The previous prime is 21373171. The next prime is 21373207. The reversal of 21373205 is 50237312.

It is not a de Polignac number, because 21373205 - 2¹⁰ = 21372181 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 (21373207) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9980 + ... + 11930.

It is an arithmetic number, because the mean of its divisors is an integer number (1838784).

Almost surely, 2^21373205 is an apocalyptic number.

It is an amenable number.

21373205 is a deficient number, since it is larger than the sum of its proper divisors (8047339).

21373205 is a wasteful number, since it uses less digits than its factorization.

21373205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2276.

The product of its (nonzero) digits is 1260, while the sum is 23.

The square root of 21373205 is about 4623.1163731838. The cubic root of 21373205 is about 277.5171863933.

The spelling of 21373205 in words is "twenty-one million, three hundred seventy-three thousand, two hundred five".