19947869 has 2 divisors, whose sum is σ = 19947870. Its totient is φ = 19947868.

The previous prime is 19947797. The next prime is 19947871. The reversal of 19947869 is 96874991.

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., 14364100 + 5583769 = 3790^2 + 2363^2 .

It is a cyclic number.

It is not a de Polignac number, because 19947869 - 2¹² = 19943773 is a prime.

It is a super-2 number, since 2×19947869² = 795834955282322, which contains 22 as substring.

Together with 19947871, it forms a pair of twin primes.

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 19947869.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19947269) 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, 9973934 + 9973935.

It is an arithmetic number, because the mean of its divisors is an integer number (9973935).

Almost surely, 2^19947869 is an apocalyptic number.

It is an amenable number.

19947869 is a deficient number, since it is larger than the sum of its proper divisors (1).

19947869 is an equidigital number, since it uses as much as digits as its factorization.

19947869 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 979776, while the sum is 53.

The square root of 19947869 is about 4466.3037290359. The cubic root of 19947869 is about 271.2057142762.

The spelling of 19947869 in words is "nineteen million, nine hundred forty-seven thousand, eight hundred sixty-nine".