219921397 has 2 divisors, whose sum is σ = 219921398. Its totient is φ = 219921396.

The previous prime is 219921353. The next prime is 219921421. The reversal of 219921397 is 793129912.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 129937201 + 89984196 = 11399^2 + 9486^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-219921397 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (219921337) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 109960698 + 109960699.

It is an arithmetic number, because the mean of its divisors is an integer number (109960699).

Almost surely, 2^219921397 is an apocalyptic number.

It is an amenable number.

219921397 is a deficient number, since it is larger than the sum of its proper divisors (1).

219921397 is an equidigital number, since it uses as much as digits as its factorization.

219921397 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61236, while the sum is 43.

The square root of 219921397 is about 14829.7470308836. The cubic root of 219921397 is about 603.6091694438.

The spelling of 219921397 in words is "two hundred nineteen million, nine hundred twenty-one thousand, three hundred ninety-seven".