20102009 has 2 divisors, whose sum is σ = 20102010. Its totient is φ = 20102008.

The previous prime is 20102003. The next prime is 20102029. The reversal of 20102009 is 90020102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17935225 + 2166784 = 4235^2 + 1472^2 .

It is a cyclic number.

It is not a de Polignac number, because 20102009 - 2⁴ = 20101993 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 20101984 and 20102002.

It is not a weakly prime, because it can be changed into another prime (20102003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10051004 + 10051005.

It is an arithmetic number, because the mean of its divisors is an integer number (10051005).

Almost surely, 2^20102009 is an apocalyptic number.

It is an amenable number.

20102009 is a deficient number, since it is larger than the sum of its proper divisors (1).

20102009 is an equidigital number, since it uses as much as digits as its factorization.

20102009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 36, while the sum is 14.

The square root of 20102009 is about 4483.5264022865. The cubic root of 20102009 is about 271.9024709812.

The spelling of 20102009 in words is "twenty million, one hundred two thousand, nine".