219920809 has 2 divisors, whose sum is σ = 219920810. Its totient is φ = 219920808.

The previous prime is 219920783. The next prime is 219920893. The reversal of 219920809 is 908029912.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 180983209 + 38937600 = 13453^2 + 6240^2 .

It is a cyclic number.

It is not a de Polignac number, because 219920809 - 2¹³ = 219912617 is a prime.

It is not a weakly prime, because it can be changed into another prime (219920009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109960404 + 109960405.

It is an arithmetic number, because the mean of its divisors is an integer number (109960405).

Almost surely, 2^219920809 is an apocalyptic number.

It is an amenable number.

219920809 is a deficient number, since it is larger than the sum of its proper divisors (1).

219920809 is an equidigital number, since it uses as much as digits as its factorization.

219920809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23328, while the sum is 40.

The square root of 219920809 is about 14829.7272058524. The cubic root of 219920809 is about 603.6086314902.

The spelling of 219920809 in words is "two hundred nineteen million, nine hundred twenty thousand, eight hundred nine".