21284903 has 2 divisors, whose sum is σ = 21284904. Its totient is φ = 21284902.

The previous prime is 21284839. The next prime is 21284911. The reversal of 21284903 is 30948212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21284903 - 2⁶ = 21284839 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21284933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10642451 + 10642452.

It is an arithmetic number, because the mean of its divisors is an integer number (10642452).

Almost surely, 2^21284903 is an apocalyptic number.

21284903 is a deficient number, since it is larger than the sum of its proper divisors (1).

21284903 is an equidigital number, since it uses as much as digits as its factorization.

21284903 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 29.

The square root of 21284903 is about 4613.5564372835. The cubic root of 21284903 is about 277.1344774883.

The spelling of 21284903 in words is "twenty-one million, two hundred eighty-four thousand, nine hundred three".