215450021009 has 2 divisors, whose sum is σ = 215450021010. Its totient is φ = 215450021008.

The previous prime is 215450020949. The next prime is 215450021011. The reversal of 215450021009 is 900120054512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 130124689984 + 85325331025 = 360728^2 + 292105^2 .

It is a cyclic number.

It is not a de Polignac number, because 215450021009 - 2¹² = 215450016913 is a prime.

Together with 215450021011, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (215450021309) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 107725010504 + 107725010505.

It is an arithmetic number, because the mean of its divisors is an integer number (107725010505).

Almost surely, 2^215450021009 is an apocalyptic number.

It is an amenable number.

215450021009 is a deficient number, since it is larger than the sum of its proper divisors (1).

215450021009 is an equidigital number, since it uses as much as digits as its factorization.

215450021009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 29.

The spelling of 215450021009 in words is "two hundred fifteen billion, four hundred fifty million, twenty-one thousand, nine".