19729857 has 16 divisors (see below), whose sum is σ = 31035392. Its totient is φ = 10910160.

The previous prime is 19729849. The next prime is 19729859. The reversal of 19729857 is 75892791.

It is not a de Polignac number, because 19729857 - 2³ = 19729849 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19729859) 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, 14503 + ... + 15804.

It is an arithmetic number, because the mean of its divisors is an integer number (1939712).

Almost surely, 2^19729857 is an apocalyptic number.

It is an amenable number.

19729857 is a deficient number, since it is larger than the sum of its proper divisors (11305535).

19729857 is a wasteful number, since it uses less digits than its factorization.

19729857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30348.

The product of its digits is 317520, while the sum is 48.

The square root of 19729857 is about 4441.8303659640. The cubic root of 19729857 is about 270.2140826099.

The spelling of 19729857 in words is "nineteen million, seven hundred twenty-nine thousand, eight hundred fifty-seven".