20001865 has 16 divisors (see below), whose sum is σ = 26062848. Its totient is φ = 14648256.

The previous prime is 20001853. The next prime is 20001899. The reversal of 20001865 is 56810002.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20001865 - 2⁵ = 20001833 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7044 + ... + 9466.

It is an arithmetic number, because the mean of its divisors is an integer number (1628928).

Almost surely, 2^20001865 is an apocalyptic number.

It is an amenable number.

20001865 is a deficient number, since it is larger than the sum of its proper divisors (6060983).

20001865 is a wasteful number, since it uses less digits than its factorization.

20001865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2568.

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 20001865 is about 4472.3444634777. The cubic root of 20001865 is about 271.4501987120.

Adding to 20001865 its reverse (56810002), we get a palindrome (76811867).

The spelling of 20001865 in words is "twenty million, one thousand, eight hundred sixty-five".