19806481 has 2 divisors, whose sum is σ = 19806482. Its totient is φ = 19806480.

The previous prime is 19806469. The next prime is 19806491. The reversal of 19806481 is 18460891.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19140625 + 665856 = 4375^2 + 816^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19806481 is a prime.

It is a super-2 number, since 2×19806481² = 784593379206722, which contains 22 as substring.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19806481.

It is not a weakly prime, because it can be changed into another prime (19806401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9903240 + 9903241.

It is an arithmetic number, because the mean of its divisors is an integer number (9903241).

Almost surely, 2^19806481 is an apocalyptic number.

It is an amenable number.

19806481 is a deficient number, since it is larger than the sum of its proper divisors (1).

19806481 is an equidigital number, since it uses as much as digits as its factorization.

19806481 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 37.

The square root of 19806481 is about 4450.4472808921. The cubic root of 19806481 is about 270.5634370256.

The spelling of 19806481 in words is "nineteen million, eight hundred six thousand, four hundred eighty-one".