16219421 has 2 divisors, whose sum is σ = 16219422. Its totient is φ = 16219420.

The previous prime is 16219403. The next prime is 16219429. The reversal of 16219421 is 12491261.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11868025 + 4351396 = 3445^2 + 2086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-16219421 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 (16219429) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 8109710 + 8109711.

It is an arithmetic number, because the mean of its divisors is an integer number (8109711).

Almost surely, 2^16219421 is an apocalyptic number.

It is an amenable number.

16219421 is a deficient number, since it is larger than the sum of its proper divisors (1).

16219421 is an equidigital number, since it uses as much as digits as its factorization.

16219421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 864, while the sum is 26.

The square root of 16219421 is about 4027.3342299839. The cubic root of 16219421 is about 253.1308722105.

The spelling of 16219421 in words is "sixteen million, two hundred nineteen thousand, four hundred twenty-one".