21283291 has 2 divisors, whose sum is σ = 21283292. Its totient is φ = 21283290.

The previous prime is 21283277. The next prime is 21283307. The reversal of 21283291 is 19238212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21283291 - 2⁵ = 21283259 is a prime.

It is not a weakly prime, because it can be changed into another prime (21283261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10641645 + 10641646.

It is an arithmetic number, because the mean of its divisors is an integer number (10641646).

Almost surely, 2^21283291 is an apocalyptic number.

21283291 is a deficient number, since it is larger than the sum of its proper divisors (1).

21283291 is an equidigital number, since it uses as much as digits as its factorization.

21283291 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1728, while the sum is 28.

The square root of 21283291 is about 4613.3817314417. The cubic root of 21283291 is about 277.1274811044.

The spelling of 21283291 in words is "twenty-one million, two hundred eighty-three thousand, two hundred ninety-one".