21403211 has 2 divisors, whose sum is σ = 21403212. Its totient is φ = 21403210.

The previous prime is 21403199. The next prime is 21403229. The reversal of 21403211 is 11230412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21403211 - 2¹⁰ = 21402187 is a prime.

It is a super-2 number, since 2×21403211² = 916194882221042, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21403241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10701605 + 10701606.

It is an arithmetic number, because the mean of its divisors is an integer number (10701606).

Almost surely, 2^21403211 is an apocalyptic number.

21403211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21403211 is an equidigital number, since it uses as much as digits as its factorization.

21403211 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 14.

The square root of 21403211 is about 4626.3604485600. The cubic root of 21403211 is about 277.6469951401.

Adding to 21403211 its reverse (11230412), we get a palindrome (32633623).

The spelling of 21403211 in words is "twenty-one million, four hundred three thousand, two hundred eleven".