213040021 has 2 divisors, whose sum is σ = 213040022. Its totient is φ = 213040020.

The previous prime is 213040013. The next prime is 213040031. The reversal of 213040021 is 120040312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 166048996 + 46991025 = 12886^2 + 6855^2 .

It is a cyclic number.

It is not a de Polignac number, because 213040021 - 2³ = 213040013 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 213039983 and 213040010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213040031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106520010 + 106520011.

It is an arithmetic number, because the mean of its divisors is an integer number (106520011).

Almost surely, 2^213040021 is an apocalyptic number.

It is an amenable number.

213040021 is a deficient number, since it is larger than the sum of its proper divisors (1).

213040021 is an equidigital number, since it uses as much as digits as its factorization.

213040021 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 13.

The square root of 213040021 is about 14595.8905517957. The cubic root of 213040021 is about 597.2466632582.

Adding to 213040021 its reverse (120040312), we get a palindrome (333080333).

The spelling of 213040021 in words is "two hundred thirteen million, forty thousand, twenty-one".