19871005 has 16 divisors (see below), whose sum is σ = 29729664. Its totient is φ = 12386880.

The previous prime is 19870999. The next prime is 19871021. The reversal of 19871005 is 50017891.

It is not a de Polignac number, because 19871005 - 2⁵ = 19870973 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25422 + ... + 26191.

It is an arithmetic number, because the mean of its divisors is an integer number (1858104).

Almost surely, 2^19871005 is an apocalyptic number.

It is an amenable number.

19871005 is a deficient number, since it is larger than the sum of its proper divisors (9858659).

19871005 is a wasteful number, since it uses less digits than its factorization.

19871005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51636.

The product of its (nonzero) digits is 2520, while the sum is 31.

The square root of 19871005 is about 4457.6905455628. The cubic root of 19871005 is about 270.8569253347.

Adding to 19871005 its reverse (50017891), we get a palindrome (69888896).

It can be divided in two parts, 1987 and 1005, that added together give a palindrome (2992).

The spelling of 19871005 in words is "nineteen million, eight hundred seventy-one thousand, five".