21009883 has 2 divisors, whose sum is σ = 21009884. Its totient is φ = 21009882.

The previous prime is 21009871. The next prime is 21009887. The reversal of 21009883 is 38890012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21009883 - 2⁵ = 21009851 is a prime.

It is not a weakly prime, because it can be changed into another prime (21009887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10504941 + 10504942.

It is an arithmetic number, because the mean of its divisors is an integer number (10504942).

Almost surely, 2^21009883 is an apocalyptic number.

21009883 is a deficient number, since it is larger than the sum of its proper divisors (1).

21009883 is an equidigital number, since it uses as much as digits as its factorization.

21009883 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 31.

The square root of 21009883 is about 4583.6538918204. The cubic root of 21009883 is about 275.9356909260.

Adding to 21009883 its reverse (38890012), we get a palindrome (59899895).

The spelling of 21009883 in words is "twenty-one million, nine thousand, eight hundred eighty-three".