20581613 has 8 divisors (see below), whose sum is σ = 22880256. Its totient is φ = 18385200.

The previous prime is 20581609. The next prime is 20581643. The reversal of 20581613 is 31618502.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20581613 - 2² = 20581609 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20581643) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 25133 + ... + 25938.

It is an arithmetic number, because the mean of its divisors is an integer number (2860032).

Almost surely, 2^20581613 is an apocalyptic number.

It is an amenable number.

20581613 is a deficient number, since it is larger than the sum of its proper divisors (2298643).

20581613 is a wasteful number, since it uses less digits than its factorization.

20581613 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51115.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 20581613 is about 4536.6962649047. The cubic root of 20581613 is about 274.0478941976.

It can be divided in two parts, 205 and 81613, that added together give a palindrome (81818).

The spelling of 20581613 in words is "twenty million, five hundred eighty-one thousand, six hundred thirteen".