19857913 has 4 divisors (see below), whose sum is σ = 20054628. Its totient is φ = 19661200.

The previous prime is 19857889. The next prime is 19857931. The reversal of 19857913 is 31975891.

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

It can be written as a sum of positive squares in 2 ways, for example, as 9566649 + 10291264 = 3093^2 + 3208^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-19857913 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 19857913.

It is not an unprimeable number, because it can be changed into a prime (19857973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 98206 + ... + 98407.

It is an arithmetic number, because the mean of its divisors is an integer number (5013657).

Almost surely, 2^19857913 is an apocalyptic number.

It is an amenable number.

19857913 is a deficient number, since it is larger than the sum of its proper divisors (196715).

19857913 is a wasteful number, since it uses less digits than its factorization.

19857913 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196714.

The product of its digits is 68040, while the sum is 43.

The square root of 19857913 is about 4456.2218302055. The cubic root of 19857913 is about 270.7974276240.

The spelling of 19857913 in words is "nineteen million, eight hundred fifty-seven thousand, nine hundred thirteen".