21966019 has 2 divisors, whose sum is σ = 21966020. Its totient is φ = 21966018.

The previous prime is 21965987. The next prime is 21966053. The reversal of 21966019 is 91066912.

It is an a-pointer prime, because the next prime (21966053) can be obtained adding 21966019 to its sum of digits (34).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21966019 - 2⁵ = 21965987 is a prime.

It is a super-2 number, since 2×21966019² = 965011981416722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21967019) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10983009 + 10983010.

It is an arithmetic number, because the mean of its divisors is an integer number (10983010).

Almost surely, 2^21966019 is an apocalyptic number.

21966019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21966019 is an equidigital number, since it uses as much as digits as its factorization.

21966019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5832, while the sum is 34.

The square root of 21966019 is about 4686.7919731945. The cubic root of 21966019 is about 280.0595919081.

The spelling of 21966019 in words is "twenty-one million, nine hundred sixty-six thousand, nineteen".