19826381 has 2 divisors, whose sum is σ = 19826382. Its totient is φ = 19826380.

The previous prime is 19826377. The next prime is 19826423. The reversal of 19826381 is 18362891.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16273156 + 3553225 = 4034^2 + 1885^2 .

It is a cyclic number.

It is not a de Polignac number, because 19826381 - 2² = 19826377 is a prime.

It is a super-2 number, since 2×19826381² = 786170767114322, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen 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 (19826321) 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, 9913190 + 9913191.

It is an arithmetic number, because the mean of its divisors is an integer number (9913191).

Almost surely, 2^19826381 is an apocalyptic number.

It is an amenable number.

19826381 is a deficient number, since it is larger than the sum of its proper divisors (1).

19826381 is an equidigital number, since it uses as much as digits as its factorization.

19826381 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 20736, while the sum is 38.

The square root of 19826381 is about 4452.6824499396. The cubic root of 19826381 is about 270.6540203417.

The spelling of 19826381 in words is "nineteen million, eight hundred twenty-six thousand, three hundred eighty-one".