19917089 has 4 divisors (see below), whose sum is σ = 19964820. Its totient is φ = 19869360.

The previous prime is 19917067. The next prime is 19917167. The reversal of 19917089 is 98071991.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 846400 + 19070689 = 920^2 + 4367^2 .

It is a cyclic number.

It is not a de Polignac number, because 19917089 - 2²⁰ = 18868513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19917389) 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 3 ways as a sum of consecutive naturals, for example, 23234 + ... + 24075.

It is an arithmetic number, because the mean of its divisors is an integer number (4991205).

Almost surely, 2^19917089 is an apocalyptic number.

It is an amenable number.

19917089 is a deficient number, since it is larger than the sum of its proper divisors (47731).

19917089 is an equidigital number, since it uses as much as digits as its factorization.

19917089 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47730.

The product of its (nonzero) digits is 40824, while the sum is 44.

The square root of 19917089 is about 4462.8565963965. The cubic root of 19917089 is about 271.0661503435.

The spelling of 19917089 in words is "nineteen million, nine hundred seventeen thousand, eighty-nine".