21366705 has 16 divisors (see below), whose sum is σ = 36198144. Its totient is φ = 10725120.

The previous prime is 21366689. The next prime is 21366713. The reversal of 21366705 is 50766312.

It is not a de Polignac number, because 21366705 - 2⁴ = 21366689 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 41641 + ... + 42150.

It is an arithmetic number, because the mean of its divisors is an integer number (2262384).

Almost surely, 2^21366705 is an apocalyptic number.

It is an amenable number.

21366705 is a deficient number, since it is larger than the sum of its proper divisors (14831439).

21366705 is a wasteful number, since it uses less digits than its factorization.

21366705 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83816.

The product of its (nonzero) digits is 7560, while the sum is 30.

The square root of 21366705 is about 4622.4133307181. The cubic root of 21366705 is about 277.4890507814.

The spelling of 21366705 in words is "twenty-one million, three hundred sixty-six thousand, seven hundred five".