206716621 has 2 divisors, whose sum is σ = 206716622. Its totient is φ = 206716620.

The previous prime is 206716613. The next prime is 206716673. The reversal of 206716621 is 126617602.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 149108521 + 57608100 = 12211^2 + 7590^2 .

It is a cyclic number.

It is not a de Polignac number, because 206716621 - 2³ = 206716613 is a prime.

It is a super-2 number, since 2×206716621² = 85463522795315282, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206716681) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103358310 + 103358311.

It is an arithmetic number, because the mean of its divisors is an integer number (103358311).

Almost surely, 2^206716621 is an apocalyptic number.

It is an amenable number.

206716621 is a deficient number, since it is larger than the sum of its proper divisors (1).

206716621 is an equidigital number, since it uses as much as digits as its factorization.

206716621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6048, while the sum is 31.

The square root of 206716621 is about 14377.6430961406. The cubic root of 206716621 is about 591.2781073578.

The spelling of 206716621 in words is "two hundred six million, seven hundred sixteen thousand, six hundred twenty-one".