21260851 has 2 divisors, whose sum is σ = 21260852. Its totient is φ = 21260850.

The previous prime is 21260849. The next prime is 21260881. The reversal of 21260851 is 15806212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21260851 - 2¹ = 21260849 is a prime.

Together with 21260849, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (21260801) by changing a digit.

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 as a sum of consecutive naturals, namely, 10630425 + 10630426.

It is an arithmetic number, because the mean of its divisors is an integer number (10630426).

Almost surely, 2^21260851 is an apocalyptic number.

21260851 is a deficient number, since it is larger than the sum of its proper divisors (1).

21260851 is an equidigital number, since it uses as much as digits as its factorization.

21260851 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 960, while the sum is 25.

The square root of 21260851 is about 4610.9490346348. The cubic root of 21260851 is about 277.0300505656.

The spelling of 21260851 in words is "twenty-one million, two hundred sixty thousand, eight hundred fifty-one".