21285347 has 2 divisors, whose sum is σ = 21285348. Its totient is φ = 21285346.

The previous prime is 21285337. The next prime is 21285367. The reversal of 21285347 is 74358212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21285347 - 2⁴ = 21285331 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21285317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10642673 + 10642674.

It is an arithmetic number, because the mean of its divisors is an integer number (10642674).

Almost surely, 2^21285347 is an apocalyptic number.

21285347 is a deficient number, since it is larger than the sum of its proper divisors (1).

21285347 is an equidigital number, since it uses as much as digits as its factorization.

21285347 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13440, while the sum is 32.

The square root of 21285347 is about 4613.6045560928. The cubic root of 21285347 is about 277.1364044700.

The spelling of 21285347 in words is "twenty-one million, two hundred eighty-five thousand, three hundred forty-seven".