19871697 has 4 divisors (see below), whose sum is σ = 26495600. Its totient is φ = 13247796.

The previous prime is 19871689. The next prime is 19871717. The reversal of 19871697 is 79617891.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 19871697 - 2³ = 19871689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19871197) 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, 3311947 + ... + 3311952.

It is an arithmetic number, because the mean of its divisors is an integer number (6623900).

Almost surely, 2^19871697 is an apocalyptic number.

It is an amenable number.

19871697 is a deficient number, since it is larger than the sum of its proper divisors (6623903).

19871697 is an equidigital number, since it uses as much as digits as its factorization.

19871697 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6623902.

The product of its digits is 190512, while the sum is 48.

The square root of 19871697 is about 4457.7681635545. The cubic root of 19871697 is about 270.8600694605.

The spelling of 19871697 in words is "nineteen million, eight hundred seventy-one thousand, six hundred ninety-seven".