19999985 has 8 divisors (see below), whose sum is σ = 24032616.
Its totient is φ = 15978240.
The previous prime is 19999981. The next prime is 19999999. The reversal of 19999985 is 58999991.
It can be written as a sum of positive squares in 4 ways, for example, as 3418801 + 16581184 = 1849^2 + 4072^2
It is a sphenic number, since it is the product of 3 distinct primes.
It is not a de Polignac number, because 19999985 - 22 = 19999981 is a prime.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (19999981) 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, 2105 + ... + 6665.
It is an arithmetic number, because the mean of its divisors is an integer number (3004077).
Almost surely, 219999985 is an apocalyptic number.
It is an amenable number.
19999985 is a deficient number, since it is larger than the sum of its proper divisors (4032631).
19999985 is an equidigital number, since it uses as much as digits as its factorization.
19999985 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 5443.
The product of its digits is 2361960, while the sum is 59.
The square root of 19999985 is about 4472.1342779483.
The cubic root of 19999985 is about 271.4416937990.
The spelling of 19999985 in words is "nineteen million, nine hundred ninety-nine thousand, nine hundred eighty-five".