213211021 has 2 divisors, whose sum is σ = 213211022. Its totient is φ = 213211020.

The previous prime is 213211007. The next prime is 213211039. The reversal of 213211021 is 120112312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 212838921 + 372100 = 14589^2 + 610^2 .

It is a cyclic number.

It is not a de Polignac number, because 213211021 - 2¹¹ = 213208973 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 213210992 and 213211010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213211001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106605510 + 106605511.

It is an arithmetic number, because the mean of its divisors is an integer number (106605511).

Almost surely, 2^213211021 is an apocalyptic number.

It is an amenable number.

213211021 is a deficient number, since it is larger than the sum of its proper divisors (1).

213211021 is an equidigital number, since it uses as much as digits as its factorization.

213211021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24, while the sum is 13.

The square root of 213211021 is about 14601.7471899770. The cubic root of 213211021 is about 597.4064170702.

Adding to 213211021 its reverse (120112312), we get a palindrome (333323333).

The spelling of 213211021 in words is "two hundred thirteen million, two hundred eleven thousand, twenty-one".