21282643 has 2 divisors, whose sum is σ = 21282644. Its totient is φ = 21282642.

The previous prime is 21282629. The next prime is 21282661. The reversal of 21282643 is 34628212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21282643 is a prime.

It is not a weakly prime, because it can be changed into another prime (21282043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10641321 + 10641322.

It is an arithmetic number, because the mean of its divisors is an integer number (10641322).

Almost surely, 2^21282643 is an apocalyptic number.

21282643 is a deficient number, since it is larger than the sum of its proper divisors (1).

21282643 is an equidigital number, since it uses as much as digits as its factorization.

21282643 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 28.

The square root of 21282643 is about 4613.3115004300. The cubic root of 21282643 is about 277.1246685627.

The spelling of 21282643 in words is "twenty-one million, two hundred eighty-two thousand, six hundred forty-three".