19981915 has 8 divisors (see below), whose sum is σ = 24087168. Its totient is φ = 15912960.

The previous prime is 19981891. The next prime is 19981933. The reversal of 19981915 is 51918991.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a de Polignac number, because none of the positive numbers 2^k-19981915 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 7846 + ... + 10075.

It is an arithmetic number, because the mean of its divisors is an integer number (3010896).

Almost surely, 2^19981915 is an apocalyptic number.

19981915 is a deficient number, since it is larger than the sum of its proper divisors (4105253).

19981915 is a wasteful number, since it uses less digits than its factorization.

19981915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18149.

The product of its digits is 29160, while the sum is 43.

The square root of 19981915 is about 4470.1135332338. The cubic root of 19981915 is about 271.3599199151.

The spelling of 19981915 in words is "nineteen million, nine hundred eighty-one thousand, nine hundred fifteen".