21206265 has 8 divisors (see below), whose sum is σ = 33930048. Its totient is φ = 11310000.

The previous prime is 21206249. The next prime is 21206303. The reversal of 21206265 is 56260212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21206265 - 2⁴ = 21206249 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 706861 + ... + 706890.

It is an arithmetic number, because the mean of its divisors is an integer number (4241256).

Almost surely, 2^21206265 is an apocalyptic number.

It is an amenable number.

21206265 is a deficient number, since it is larger than the sum of its proper divisors (12723783).

21206265 is a wasteful number, since it uses less digits than its factorization.

21206265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1413759.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 21206265 is about 4605.0260585582. The cubic root of 21206265 is about 276.7927611862.

Adding to 21206265 its reverse (56260212), we get a palindrome (77466477).

It can be divided in two parts, 2120 and 6265, that added together give a triangular number (8385 = T₁₂₉).

The spelling of 21206265 in words is "twenty-one million, two hundred six thousand, two hundred sixty-five".