19915 has 8 divisors (see below), whose sum is σ = 27360. Its totient is φ = 13632.

The previous prime is 19913. The next prime is 19919. The reversal of 19915 is 51991.

19915 = 31² + 32² + ... + 44².

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

It is a cyclic number.

It is not a de Polignac number, because 19915 - 2¹ = 19913 is a prime.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 19915.

It is not an unprimeable number, because it can be changed into a prime (19913) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 250 + ... + 319.

It is an arithmetic number, because the mean of its divisors is an integer number (3420).

2¹⁹⁹¹⁵ is an apocalyptic number.

19915 is a deficient number, since it is larger than the sum of its proper divisors (7445).

19915 is an equidigital number, since it uses as much as digits as its factorization.

19915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 581.

The product of its digits is 405, while the sum is 25.

The square root of 19915 is about 141.1205158721. The cubic root of 19915 is about 27.1056673105.

The spelling of 19915 in words is "nineteen thousand, nine hundred fifteen".