206663621 has 2 divisors, whose sum is σ = 206663622. Its totient is φ = 206663620.

The previous prime is 206663617. The next prime is 206663651. The reversal of 206663621 is 126366602.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 131217025 + 75446596 = 11455^2 + 8686^2 .

It is a cyclic number.

It is not a de Polignac number, because 206663621 - 2² = 206663617 is a prime.

It is a Chen prime.

It is equal to p_11427296 and since 206663621 and 11427296 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (206663651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103331810 + 103331811.

It is an arithmetic number, because the mean of its divisors is an integer number (103331811).

Almost surely, 2^206663621 is an apocalyptic number.

It is an amenable number.

206663621 is a deficient number, since it is larger than the sum of its proper divisors (1).

206663621 is an equidigital number, since it uses as much as digits as its factorization.

206663621 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 15552, while the sum is 32.

The square root of 206663621 is about 14375.7998386177. The cubic root of 206663621 is about 591.2275705115.

The spelling of 206663621 in words is "two hundred six million, six hundred sixty-three thousand, six hundred twenty-one".