21283331 has 2 divisors, whose sum is σ = 21283332. Its totient is φ = 21283330.

The previous prime is 21283319. The next prime is 21283333. The reversal of 21283331 is 13338212.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21283331 is a prime.

It is a super-2 number, since 2×21283331² = 905960356911122, which contains 22 as substring.

Together with 21283333, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 21283297 and 21283306.

It is not a weakly prime, because it can be changed into another prime (21283333) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10641665 + 10641666.

It is an arithmetic number, because the mean of its divisors is an integer number (10641666).

Almost surely, 2^21283331 is an apocalyptic number.

21283331 is a deficient number, since it is larger than the sum of its proper divisors (1).

21283331 is an equidigital number, since it uses as much as digits as its factorization.

21283331 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 23.

The square root of 21283331 is about 4613.3860666543. The cubic root of 21283331 is about 277.1276547163.

The spelling of 21283331 in words is "twenty-one million, two hundred eighty-three thousand, three hundred thirty-one".