21284741 has 2 divisors, whose sum is σ = 21284742. Its totient is φ = 21284740.

The previous prime is 21284723. The next prime is 21284743. The reversal of 21284741 is 14748212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14984641 + 6300100 = 3871^2 + 2510^2 .

It is a cyclic number.

It is not a de Polignac number, because 21284741 - 2⁶ = 21284677 is a prime.

Together with 21284743, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21284743) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10642370 + 10642371.

It is an arithmetic number, because the mean of its divisors is an integer number (10642371).

Almost surely, 2^21284741 is an apocalyptic number.

It is an amenable number.

21284741 is a deficient number, since it is larger than the sum of its proper divisors (1).

21284741 is an equidigital number, since it uses as much as digits as its factorization.

21284741 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3584, while the sum is 29.

The square root of 21284741 is about 4613.5388802957. The cubic root of 21284741 is about 277.1337743937.

The spelling of 21284741 in words is "twenty-one million, two hundred eighty-four thousand, seven hundred forty-one".