19813985 has 8 divisors (see below), whose sum is σ = 23987880. Its totient is φ = 15710464.

The previous prime is 19813967. The next prime is 19813987. The reversal of 19813985 is 58931891.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 2140369 + 17673616 = 1463^2 + 4204^2 .

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 19813985 - 2¹⁸ = 19551841 is a prime.

It is a super-3 number, since 3×19813985³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (19813987) 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, 16970 + ... + 18099.

It is an arithmetic number, because the mean of its divisors is an integer number (2998485).

Almost surely, 2^19813985 is an apocalyptic number.

It is an amenable number.

19813985 is a deficient number, since it is larger than the sum of its proper divisors (4173895).

19813985 is a wasteful number, since it uses less digits than its factorization.

19813985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 35187.

The product of its digits is 77760, while the sum is 44.

The square root of 19813985 is about 4451.2902623846. The cubic root of 19813985 is about 270.5976017969.

The spelling of 19813985 in words is "nineteen million, eight hundred thirteen thousand, nine hundred eighty-five".