20018865 has 32 divisors (see below), whose sum is σ = 33618816. Its totient is φ = 10160640.

The previous prime is 20018849. The next prime is 20018881. The reversal of 20018865 is 56881002.

It is an interprime number because it is at equal distance from previous prime (20018849) and next prime (20018881).

It is not a de Polignac number, because 20018865 - 2⁴ = 20018849 is a prime.

It is an unprimeable number.

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 31 ways as a sum of consecutive naturals, for example, 26067 + ... + 26823.

It is an arithmetic number, because the mean of its divisors is an integer number (1050588).

Almost surely, 2^20018865 is an apocalyptic number.

It is an amenable number.

20018865 is a deficient number, since it is larger than the sum of its proper divisors (13599951).

20018865 is a wasteful number, since it uses less digits than its factorization.

20018865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 849.

The product of its (nonzero) digits is 3840, while the sum is 30.

The square root of 20018865 is about 4474.2446289849. The cubic root of 20018865 is about 271.5270806533.

Adding to 20018865 its reverse (56881002), we get a palindrome (76899867).

The spelling of 20018865 in words is "twenty million, eighteen thousand, eight hundred sixty-five".