19845009 has 6 divisors (see below), whose sum is σ = 28665026. Its totient is φ = 13230000.

The previous prime is 19844989. The next prime is 19845011. The reversal of 19845009 is 90054891.

It can be written as a sum of positive squares in only one way, i.e., 14085009 + 5760000 = 3753^2 + 2400^2 .

It is not a de Polignac number, because 19845009 - 2⁸ = 19844753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19845029) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1102492 + ... + 1102509.

Almost surely, 2^19845009 is an apocalyptic number.

It is an amenable number.

19845009 is a deficient number, since it is larger than the sum of its proper divisors (8820017).

19845009 is a wasteful number, since it uses less digits than its factorization.

19845009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2205007 (or 2205004 counting only the distinct ones).

The product of its (nonzero) digits is 12960, while the sum is 36.

The square root of 19845009 is about 4454.7737316277. The cubic root of 19845009 is about 270.7387586997.

The spelling of 19845009 in words is "nineteen million, eight hundred forty-five thousand, nine".