10206821 has 2 divisors, whose sum is σ = 10206822. Its totient is φ = 10206820.

The previous prime is 10206809. The next prime is 10206839. The reversal of 10206821 is 12860201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6558721 + 3648100 = 2561^2 + 1910^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-10206821 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 10206793 and 10206802.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (10206121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5103410 + 5103411.

It is an arithmetic number, because the mean of its divisors is an integer number (5103411).

Almost surely, 2^10206821 is an apocalyptic number.

It is an amenable number.

10206821 is a deficient number, since it is larger than the sum of its proper divisors (1).

10206821 is an equidigital number, since it uses as much as digits as its factorization.

10206821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 192, while the sum is 20.

The square root of 10206821 is about 3194.8115750385. The cubic root of 10206821 is about 216.9186199831.

The spelling of 10206821 in words is "ten million, two hundred six thousand, eight hundred twenty-one".