219810121 has 2 divisors, whose sum is σ = 219810122. Its totient is φ = 219810120.

The previous prime is 219810113. The next prime is 219810127. The reversal of 219810121 is 121018912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 142563600 + 77246521 = 11940^2 + 8789^2 .

It is a cyclic number.

It is not a de Polignac number, because 219810121 - 2³ = 219810113 is a prime.

It is not a weakly prime, because it can be changed into another prime (219810127) 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, 109905060 + 109905061.

It is an arithmetic number, because the mean of its divisors is an integer number (109905061).

Almost surely, 2^219810121 is an apocalyptic number.

It is an amenable number.

219810121 is a deficient number, since it is larger than the sum of its proper divisors (1).

219810121 is an equidigital number, since it uses as much as digits as its factorization.

219810121 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 25.

The square root of 219810121 is about 14825.9947726957. The cubic root of 219810121 is about 603.5073473890.

The spelling of 219810121 in words is "two hundred nineteen million, eight hundred ten thousand, one hundred twenty-one".