19996999 has 4 divisors (see below), whose sum is σ = 21814920. Its totient is φ = 18179080.

The previous prime is 19996993. The next prime is 19997011. The reversal of 19996999 is 99969991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99969991 = 11 ⋅9088181.

It is a cyclic number.

It is not a de Polignac number, because 19996999 - 2⁷ = 19996871 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19996993) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 908944 + ... + 908965.

It is an arithmetic number, because the mean of its divisors is an integer number (5453730).

Almost surely, 2^19996999 is an apocalyptic number.

19996999 is a deficient number, since it is larger than the sum of its proper divisors (1817921).

19996999 is a wasteful number, since it uses less digits than its factorization.

19996999 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1817920.

The product of its digits is 3188646, while the sum is 61.

The square root of 19996999 is about 4471.8004204123. The cubic root of 19996999 is about 271.4281843683.

It can be divided in two parts, 1999 and 6999, that added together give a palindrome (8998).

The spelling of 19996999 in words is "nineteen million, nine hundred ninety-six thousand, nine hundred ninety-nine".