20391385 has 16 divisors (see below), whose sum is σ = 28426752. Its totient is φ = 13752000.

The previous prime is 20391377. The next prime is 20391407. The reversal of 20391385 is 58319302.

It is a happy number.

It is not a de Polignac number, because 20391385 - 2³ = 20391377 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, 2641 + ... + 6910.

It is an arithmetic number, because the mean of its divisors is an integer number (1776672).

Almost surely, 2^20391385 is an apocalyptic number.

It is an amenable number.

20391385 is a deficient number, since it is larger than the sum of its proper divisors (8035367).

20391385 is an equidigital number, since it uses as much as digits as its factorization.

20391385 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9624.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 20391385 is about 4515.6821190159. The cubic root of 20391385 is about 273.2009728312.

The spelling of 20391385 in words is "twenty million, three hundred ninety-one thousand, three hundred eighty-five".