213622021 has 2 divisors, whose sum is σ = 213622022. Its totient is φ = 213622020.

The previous prime is 213622009. The next prime is 213622049. The reversal of 213622021 is 120226312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 108784900 + 104837121 = 10430^2 + 10239^2 .

It is a cyclic number.

It is not a de Polignac number, because 213622021 - 2⁹ = 213621509 is a prime.

It is a super-2 number, since 2×213622021² = 91268735712248882, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 213622021.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213622121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106811010 + 106811011.

It is an arithmetic number, because the mean of its divisors is an integer number (106811011).

Almost surely, 2^213622021 is an apocalyptic number.

It is an amenable number.

213622021 is a deficient number, since it is larger than the sum of its proper divisors (1).

213622021 is an equidigital number, since it uses as much as digits as its factorization.

213622021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 213622021 is about 14615.8140724354. The cubic root of 213622021 is about 597.7900376974.

Adding to 213622021 its reverse (120226312), we get a palindrome (333848333).

The spelling of 213622021 in words is "two hundred thirteen million, six hundred twenty-two thousand, twenty-one".