19815485 has 12 divisors (see below), whose sum is σ = 24208212. Its totient is φ = 15568128.

The previous prime is 19815473. The next prime is 19815487. The reversal of 19815485 is 58451891.

It can be written as a sum of positive squares in 6 ways, for example, as 2393209 + 17422276 = 1547^2 + 4174^2 .

It is not a de Polignac number, because 19815485 - 2⁴ = 19815469 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19815487) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 84929 + ... + 85161.

It is an arithmetic number, because the mean of its divisors is an integer number (2017351).

Almost surely, 2^19815485 is an apocalyptic number.

It is an amenable number.

19815485 is a deficient number, since it is larger than the sum of its proper divisors (4392727).

19815485 is an frugal number, since it uses more digits than its factorization.

19815485 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 544 (or 311 counting only the distinct ones).

The product of its digits is 57600, while the sum is 41.

The square root of 19815485 is about 4451.4587496685. The cubic root of 19815485 is about 270.6044300743.

The spelling of 19815485 in words is "nineteen million, eight hundred fifteen thousand, four hundred eighty-five".