19809923 has 16 divisors (see below), whose sum is σ = 23970816. Its totient is φ = 16003680.

The previous prime is 19809919. The next prime is 19809941. The reversal of 19809923 is 32990891.

It is not a de Polignac number, because 19809923 - 2² = 19809919 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19809953) 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 15 ways as a sum of consecutive naturals, for example, 10565 + ... + 12297.

It is an arithmetic number, because the mean of its divisors is an integer number (1498176).

Almost surely, 2^19809923 is an apocalyptic number.

19809923 is a deficient number, since it is larger than the sum of its proper divisors (4160893).

19809923 is a wasteful number, since it uses less digits than its factorization.

19809923 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1834.

The product of its (nonzero) digits is 34992, while the sum is 41.

The square root of 19809923 is about 4450.8339667977. The cubic root of 19809923 is about 270.5791090912.

The spelling of 19809923 in words is "nineteen million, eight hundred nine thousand, nine hundred twenty-three".