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20304581 = 119711901
BaseRepresentation
bin100110101110…
…1001011000101
31102012120122112
41031131023011
520144221311
62003110405
7334405013
oct115351305
942176575
1020304581
1110509150
126972405
13428bc5b
1429a78b3
151bb128b
hex135d2c5

20304581 has 8 divisors (see below), whose sum is σ = 22184928. Its totient is φ = 18430000.

The previous prime is 20304563. The next prime is 20304589. The reversal of 20304581 is 18540302.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-20304581 is a prime.

It is a super-2 number, since 2×203045812 = 824552019171122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20304589) 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, 9731 + ... + 11631.

It is an arithmetic number, because the mean of its divisors is an integer number (2773116).

Almost surely, 220304581 is an apocalyptic number.

It is an amenable number.

20304581 is a deficient number, since it is larger than the sum of its proper divisors (1880347).

20304581 is a wasteful number, since it uses less digits than its factorization.

20304581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2883.

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 20304581 is about 4506.0604745165. The cubic root of 20304581 is about 272.8127587606.

Adding to 20304581 its reverse (18540302), we get a palindrome (38844883).

The spelling of 20304581 in words is "twenty million, three hundred four thousand, five hundred eighty-one".

Divisors: 1 11 971 1901 10681 20911 1845871 20304581