19890915 has 16 divisors (see below), whose sum is σ = 34718976. Its totient is φ = 9644000.

The previous prime is 19890911. The next prime is 19890919. The reversal of 19890915 is 51909891.

It is an interprime number because it is at equal distance from previous prime (19890911) and next prime (19890919).

It is not a de Polignac number, because 19890915 - 2² = 19890911 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19890911) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 60111 + ... + 60440.

It is an arithmetic number, because the mean of its divisors is an integer number (2169936).

Almost surely, 2^19890915 is an apocalyptic number.

19890915 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

19890915 is a deficient number, since it is larger than the sum of its proper divisors (14828061).

19890915 is a wasteful number, since it uses less digits than its factorization.

19890915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 120570.

The product of its (nonzero) digits is 29160, while the sum is 42.

The square root of 19890915 is about 4459.9232056169. The cubic root of 19890915 is about 270.9473579571.

The spelling of 19890915 in words is "nineteen million, eight hundred ninety thousand, nine hundred fifteen".