19994779 has 4 divisors (see below), whose sum is σ = 22851184. Its totient is φ = 17138376.

The previous prime is 19994761. The next prime is 19994789. The reversal of 19994779 is 97749991.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 19994779 - 2⁹ = 19994267 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19994729) 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, 1428192 + ... + 1428205.

It is an arithmetic number, because the mean of its divisors is an integer number (5712796).

Almost surely, 2^19994779 is an apocalyptic number.

19994779 is a deficient number, since it is larger than the sum of its proper divisors (2856405).

19994779 is an equidigital number, since it uses as much as digits as its factorization.

19994779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2856404.

The product of its digits is 1285956, while the sum is 55.

The square root of 19994779 is about 4471.5521913537. The cubic root of 19994779 is about 271.4181396466.

The spelling of 19994779 in words is "nineteen million, nine hundred ninety-four thousand, seven hundred seventy-nine".