213235621 has 2 divisors, whose sum is σ = 213235622. Its totient is φ = 213235620.

The previous prime is 213235619. The next prime is 213235657. The reversal of 213235621 is 126532312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 204175521 + 9060100 = 14289^2 + 3010^2 .

It is a cyclic number.

It is not a de Polignac number, because 213235621 - 2¹ = 213235619 is a prime.

Together with 213235619, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213235601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106617810 + 106617811.

It is an arithmetic number, because the mean of its divisors is an integer number (106617811).

Almost surely, 2^213235621 is an apocalyptic number.

It is an amenable number.

213235621 is a deficient number, since it is larger than the sum of its proper divisors (1).

213235621 is an equidigital number, since it uses as much as digits as its factorization.

213235621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2160, while the sum is 25.

The square root of 213235621 is about 14602.5895306278. The cubic root of 213235621 is about 597.4293921688.

Adding to 213235621 its reverse (126532312), we get a palindrome (339767933).

The spelling of 213235621 in words is "two hundred thirteen million, two hundred thirty-five thousand, six hundred twenty-one".