21210843 has 6 divisors (see below), whose sum is σ = 28291764. Its totient is φ = 14135244.

The previous prime is 21210841. The next prime is 21210877. The reversal of 21210843 is 34801212.

It is not a de Polignac number, because 21210843 - 2¹ = 21210841 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21210841) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6648 + ... + 9306.

It is an arithmetic number, because the mean of its divisors is an integer number (4715294).

Almost surely, 2^21210843 is an apocalyptic number.

21210843 is a deficient number, since it is larger than the sum of its proper divisors (7080921).

21210843 is an frugal number, since it uses more digits than its factorization.

21210843 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5321 (or 2662 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 21.

The square root of 21210843 is about 4605.5230973256. The cubic root of 21210843 is about 276.8126777233.

The spelling of 21210843 in words is "twenty-one million, two hundred ten thousand, eight hundred forty-three".