19887005 has 4 divisors (see below), whose sum is σ = 23864412. Its totient is φ = 15909600.

The previous prime is 19886963. The next prime is 19887017. The reversal of 19887005 is 50078891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50078891 = 461 ⋅108631.

It can be written as a sum of positive squares in 2 ways, for example, as 11042329 + 8844676 = 3323^2 + 2974^2 .

It is not a de Polignac number, because 19887005 - 2²² = 15692701 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 19887005.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1988696 + ... + 1988705.

It is an arithmetic number, because the mean of its divisors is an integer number (5966103).

Almost surely, 2^19887005 is an apocalyptic number.

It is an amenable number.

19887005 is a deficient number, since it is larger than the sum of its proper divisors (3977407).

19887005 is an equidigital number, since it uses as much as digits as its factorization.

19887005 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3977406.

The product of its (nonzero) digits is 20160, while the sum is 38.

The square root of 19887005 is about 4459.4848357181. The cubic root of 19887005 is about 270.9296032251.

The spelling of 19887005 in words is "nineteen million, eight hundred eighty-seven thousand, five".