213246821 has 2 divisors, whose sum is σ = 213246822. Its totient is φ = 213246820.

The previous prime is 213246811. The next prime is 213246829. The reversal of 213246821 is 128642312.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 190826596 + 22420225 = 13814^2 + 4735^2 .

It is a cyclic number.

It is not a de Polignac number, because 213246821 - 2⁶ = 213246757 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (213246829) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106623410 + 106623411.

It is an arithmetic number, because the mean of its divisors is an integer number (106623411).

Almost surely, 2^213246821 is an apocalyptic number.

It is an amenable number.

213246821 is a deficient number, since it is larger than the sum of its proper divisors (1).

213246821 is an equidigital number, since it uses as much as digits as its factorization.

213246821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 29.

The square root of 213246821 is about 14602.9730192177. The cubic root of 213246821 is about 597.4398517909.

The spelling of 213246821 in words is "two hundred thirteen million, two hundred forty-six thousand, eight hundred twenty-one".