21283447 has 2 divisors, whose sum is σ = 21283448. Its totient is φ = 21283446.

The previous prime is 21283417. The next prime is 21283463. The reversal of 21283447 is 74438212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21283447 - 2⁷ = 21283319 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21283417) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10641723 + 10641724.

It is an arithmetic number, because the mean of its divisors is an integer number (10641724).

Almost surely, 2^21283447 is an apocalyptic number.

21283447 is a deficient number, since it is larger than the sum of its proper divisors (1).

21283447 is an equidigital number, since it uses as much as digits as its factorization.

21283447 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10752, while the sum is 31.

The square root of 21283447 is about 4613.3986387478. The cubic root of 21283447 is about 277.1281581893.

The spelling of 21283447 in words is "twenty-one million, two hundred eighty-three thousand, four hundred forty-seven".