219190021 has 2 divisors, whose sum is σ = 219190022. Its totient is φ = 219190020.

The previous prime is 219189989. The next prime is 219190051. The reversal of 219190021 is 120091912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 216972900 + 2217121 = 14730^2 + 1489^2 .

It is a cyclic number.

It is not a de Polignac number, because 219190021 - 2⁵ = 219189989 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (219190051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109595010 + 109595011.

It is an arithmetic number, because the mean of its divisors is an integer number (109595011).

Almost surely, 2^219190021 is an apocalyptic number.

It is an amenable number.

219190021 is a deficient number, since it is larger than the sum of its proper divisors (1).

219190021 is an equidigital number, since it uses as much as digits as its factorization.

219190021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 25.

The square root of 219190021 is about 14805.0674095054. The cubic root of 219190021 is about 602.9393004895.

The spelling of 219190021 in words is "two hundred nineteen million, one hundred ninety thousand, twenty-one".