219042821 has 2 divisors, whose sum is σ = 219042822. Its totient is φ = 219042820.

The previous prime is 219042797. The next prime is 219042827. The reversal of 219042821 is 128240912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 215766721 + 3276100 = 14689^2 + 1810^2 .

It is a cyclic number.

It is not a de Polignac number, because 219042821 - 2¹⁸ = 218780677 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (219042827) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109521410 + 109521411.

It is an arithmetic number, because the mean of its divisors is an integer number (109521411).

Almost surely, 2^219042821 is an apocalyptic number.

It is an amenable number.

219042821 is a deficient number, since it is larger than the sum of its proper divisors (1).

219042821 is an equidigital number, since it uses as much as digits as its factorization.

219042821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 219042821 is about 14800.0953037472. The cubic root of 219042821 is about 602.8042996050.

The spelling of 219042821 in words is "two hundred nineteen million, forty-two thousand, eight hundred twenty-one".