21266305 has 16 divisors (see below), whose sum is σ = 26429760. Its totient is φ = 16414272.

The previous prime is 21266299. The next prime is 21266317. The reversal of 21266305 is 50366212.

It is a cyclic number.

It is not a de Polignac number, because 21266305 - 2¹⁹ = 20742017 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21266305.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25302 + ... + 26128.

It is an arithmetic number, because the mean of its divisors is an integer number (1651860).

Almost surely, 2^21266305 is an apocalyptic number.

It is an amenable number.

21266305 is a deficient number, since it is larger than the sum of its proper divisors (5163455).

21266305 is a wasteful number, since it uses less digits than its factorization.

21266305 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1008.

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

The square root of 21266305 is about 4611.5404150891. The cubic root of 21266305 is about 277.0537371797.

The spelling of 21266305 in words is "twenty-one million, two hundred sixty-six thousand, three hundred five".