21365206 has 16 divisors (see below), whose sum is σ = 34347744. Its totient is φ = 9941184.

The previous prime is 21365203. The next prime is 21365219. The reversal of 21365206 is 60256312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21365203) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4575 + ... + 7978.

It is an arithmetic number, because the mean of its divisors is an integer number (2146734).

Almost surely, 2^21365206 is an apocalyptic number.

21365206 is a deficient number, since it is larger than the sum of its proper divisors (12982538).

21365206 is a wasteful number, since it uses less digits than its factorization.

21365206 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12615.

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21365206 is about 4622.2511831358. The cubic root of 21365206 is about 277.4825614667.

The spelling of 21365206 in words is "twenty-one million, three hundred sixty-five thousand, two hundred six".