21172000610209 has 2 divisors, whose sum is σ = 21172000610210. Its totient is φ = 21172000610208.

The previous prime is 21172000610197. The next prime is 21172000610261. The reversal of 21172000610209 is 90201600027112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19664151687184 + 1507848923025 = 4434428^2 + 1227945^2 .

It is a cyclic number.

It is not a de Polignac number, because 21172000610209 - 2⁴¹ = 18972977354657 is a prime.

It is not a weakly prime, because it can be changed into another prime (21172000610009) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10586000305104 + 10586000305105.

It is an arithmetic number, because the mean of its divisors is an integer number (10586000305105).

Almost surely, 2^{21172000610209} is an apocalyptic number.

It is an amenable number.

21172000610209 is a deficient number, since it is larger than the sum of its proper divisors (1).

21172000610209 is an equidigital number, since it uses as much as digits as its factorization.

21172000610209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 31.

The spelling of 21172000610209 in words is "twenty-one trillion, one hundred seventy-two billion, six hundred ten thousand, two hundred nine".