19987433 has 2 divisors, whose sum is σ = 19987434. Its totient is φ = 19987432.

The previous prime is 19987403. The next prime is 19987453. The reversal of 19987433 is 33478991.

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., 11478544 + 8508889 = 3388^2 + 2917^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19987433 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (19987403) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9993716 + 9993717.

It is an arithmetic number, because the mean of its divisors is an integer number (9993717).

Almost surely, 2^19987433 is an apocalyptic number.

It is an amenable number.

19987433 is a deficient number, since it is larger than the sum of its proper divisors (1).

19987433 is an equidigital number, since it uses as much as digits as its factorization.

19987433 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 163296, while the sum is 44.

The square root of 19987433 is about 4470.7307009034. The cubic root of 19987433 is about 271.3848962704.

The spelling of 19987433 in words is "nineteen million, nine hundred eighty-seven thousand, four hundred thirty-three".