20185138865 has 16 divisors (see below), whose sum is σ = 24379367040. Its totient is φ = 16043408640.

The previous prime is 20185138861. The next prime is 20185138907. The reversal of 20185138865 is 56883158102.

It is a happy number.

It is not a de Polignac number, because 20185138865 - 2² = 20185138861 is a prime.

It is not an unprimeable number, because it can be changed into a prime (20185138861) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2115305 + ... + 2124825.

It is an arithmetic number, because the mean of its divisors is an integer number (1523710440).

Almost surely, 2^20185138865 is an apocalyptic number.

It is an amenable number.

20185138865 is a deficient number, since it is larger than the sum of its proper divisors (4194228175).

20185138865 is a wasteful number, since it uses less digits than its factorization.

20185138865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12232.

The product of its (nonzero) digits is 460800, while the sum is 47.

The spelling of 20185138865 in words is "twenty billion, one hundred eighty-five million, one hundred thirty-eight thousand, eight hundred sixty-five".