21000211 has 8 divisors (see below), whose sum is σ = 21947904. Its totient is φ = 20073480.

The previous prime is 21000193. The next prime is 21000229. The reversal of 21000211 is 11200012.

It is an interprime number because it is at equal distance from previous prime (21000193) and next prime (21000229).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21000211 - 2¹¹ = 20998163 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000194 and 21000203.

It is not an unprimeable number, because it can be changed into a prime (21000251) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3175 + ... + 7216.

It is an arithmetic number, because the mean of its divisors is an integer number (2743488).

Almost surely, 2^21000211 is an apocalyptic number.

21000211 is a deficient number, since it is larger than the sum of its proper divisors (947693).

21000211 is a wasteful number, since it uses less digits than its factorization.

21000211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10481.

The product of its (nonzero) digits is 4, while the sum is 7.

The square root of 21000211 is about 4582.5987168854. The cubic root of 21000211 is about 275.8933416557.

Adding to 21000211 its reverse (11200012), we get a palindrome (32200223).

The spelling of 21000211 in words is "twenty-one million, two hundred eleven", and thus it is an aban number.