19919797 has 2 divisors, whose sum is σ = 19919798. Its totient is φ = 19919796.

The previous prime is 19919791. The next prime is 19919803. The reversal of 19919797 is 79791991.

It is a balanced prime because it is at equal distance from previous prime (19919791) and next prime (19919803).

It can be written as a sum of positive squares in only one way, i.e., 19766916 + 152881 = 4446^2 + 391^2 .

It is a cyclic number.

It is not a de Polignac number, because 19919797 - 2³ = 19919789 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19919791) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9959898 + 9959899.

It is an arithmetic number, because the mean of its divisors is an integer number (9959899).

Almost surely, 2^19919797 is an apocalyptic number.

It is an amenable number.

19919797 is a deficient number, since it is larger than the sum of its proper divisors (1).

19919797 is an equidigital number, since it uses as much as digits as its factorization.

19919797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 321489, while the sum is 52.

The square root of 19919797 is about 4463.1599792076. The cubic root of 19919797 is about 271.0784348340.

The spelling of 19919797 in words is "nineteen million, nine hundred nineteen thousand, seven hundred ninety-seven".