19999797 has 4 divisors (see below), whose sum is σ = 26666400. Its totient is φ = 13333196.

The previous prime is 19999789. The next prime is 19999817. The reversal of 19999797 is 79799991.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 19999797 - 2³ = 19999789 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19999797.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19999297) 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 in 3 ways as a sum of consecutive naturals, for example, 3333297 + ... + 3333302.

It is an arithmetic number, because the mean of its divisors is an integer number (6666600).

Almost surely, 2^19999797 is an apocalyptic number.

It is an amenable number.

19999797 is a deficient number, since it is larger than the sum of its proper divisors (6666603).

19999797 is an equidigital number, since it uses as much as digits as its factorization.

19999797 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6666602.

The product of its digits is 2893401, while the sum is 60.

The square root of 19999797 is about 4472.1132588520. The cubic root of 19999797 is about 271.4408432784.

The spelling of 19999797 in words is "nineteen million, nine hundred ninety-nine thousand, seven hundred ninety-seven".