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20905221 = 36968407
BaseRepresentation
bin100111110111…
…1110100000101
31110100002120110
41033233310011
520322431341
62024023233
7342456111
oct117576405
943302513
1020905221
1110889447
127001b19
13443c46c
142ac2741
151c7e216
hex13efd05

20905221 has 4 divisors (see below), whose sum is σ = 27873632. Its totient is φ = 13936812.

The previous prime is 20905207. The next prime is 20905237. The reversal of 20905221 is 12250902.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 20905221 - 223 = 12516613 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 (20905921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3484201 + ... + 3484206.

It is an arithmetic number, because the mean of its divisors is an integer number (6968408).

Almost surely, 220905221 is an apocalyptic number.

It is an amenable number.

20905221 is a deficient number, since it is larger than the sum of its proper divisors (6968411).

20905221 is an equidigital number, since it uses as much as digits as its factorization.

20905221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6968410.

The product of its (nonzero) digits is 360, while the sum is 21.

The square root of 20905221 is about 4572.2227636020. Note that the first 3 decimals coincide. The cubic root of 20905221 is about 275.4767312032.

The spelling of 20905221 in words is "twenty million, nine hundred five thousand, two hundred twenty-one".

Divisors: 1 3 6968407 20905221