19887013 has 4 divisors (see below), whose sum is σ = 19997068. Its totient is φ = 19776960.

The previous prime is 19886963. The next prime is 19887017. The reversal of 19887013 is 31078891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 31078891 = 47 ⋅661253.

It can be written as a sum of positive squares in 2 ways, for example, as 1077444 + 18809569 = 1038^2 + 4337^2 .

It is a cyclic number.

It is not a de Polignac number, because 19887013 - 2¹³ = 19878821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19887017) 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, 54756 + ... + 55117.

It is an arithmetic number, because the mean of its divisors is an integer number (4999267).

Almost surely, 2^19887013 is an apocalyptic number.

It is an amenable number.

19887013 is a deficient number, since it is larger than the sum of its proper divisors (110055).

19887013 is a wasteful number, since it uses less digits than its factorization.

19887013 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 110054.

The product of its (nonzero) digits is 12096, while the sum is 37.

The square root of 19887013 is about 4459.4857326826. The cubic root of 19887013 is about 270.9296395543.

The spelling of 19887013 in words is "nineteen million, eight hundred eighty-seven thousand, thirteen".