120009821 has 2 divisors, whose sum is σ = 120009822. Its totient is φ = 120009820.

The previous prime is 120009803. The next prime is 120009823. The reversal of 120009821 is 128900021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 119661721 + 348100 = 10939^2 + 590^2 .

It is a cyclic number.

It is not a de Polignac number, because 120009821 - 2¹⁴ = 119993437 is a prime.

Together with 120009823, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (120009823) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 60004910 + 60004911.

It is an arithmetic number, because the mean of its divisors is an integer number (60004911).

Almost surely, 2^120009821 is an apocalyptic number.

It is an amenable number.

120009821 is a deficient number, since it is larger than the sum of its proper divisors (1).

120009821 is an equidigital number, since it uses as much as digits as its factorization.

120009821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 23.

The square root of 120009821 is about 10954.8994062018. The cubic root of 120009821 is about 493.2558704261.

Adding to 120009821 its reverse (128900021), we get a palindrome (248909842).

The spelling of 120009821 in words is "one hundred twenty million, nine thousand, eight hundred twenty-one".