19871047 has 4 divisors (see below), whose sum is σ = 22709776. Its totient is φ = 17032320.

The previous prime is 19871039. The next prime is 19871051. The reversal of 19871047 is 74017891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 74017891 = 7753 ⋅9547.

It is a cyclic number.

It is not a de Polignac number, because 19871047 - 2³ = 19871039 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19870997 and 19871015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19871947) 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, 1419354 + ... + 1419367.

It is an arithmetic number, because the mean of its divisors is an integer number (5677444).

Almost surely, 2^19871047 is an apocalyptic number.

19871047 is a deficient number, since it is larger than the sum of its proper divisors (2838729).

19871047 is an equidigital number, since it uses as much as digits as its factorization.

19871047 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2838728.

The product of its (nonzero) digits is 14112, while the sum is 37.

The square root of 19871047 is about 4457.6952565199. The cubic root of 19871047 is about 270.8571161653.

The spelling of 19871047 in words is "nineteen million, eight hundred seventy-one thousand, forty-seven".