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21005259 = 3113120533
BaseRepresentation
bin101000000100…
…0001111001011
31110112011210120
41100020033023
520334132014
62030114323
7343353552
oct120101713
943464716
1021005259
1110947620
12704b9a3
134475b62
142b0ad99
151c9dba9
hex14083cb

21005259 has 16 divisors (see below), whose sum is σ = 31540224. Its totient is φ = 12319200.

The previous prime is 21005227. The next prime is 21005269. The reversal of 21005259 is 95250012.

It is not a de Polignac number, because 21005259 - 25 = 21005227 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21005209) 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, 9244 + ... + 11289.

It is an arithmetic number, because the mean of its divisors is an integer number (1971264).

Almost surely, 221005259 is an apocalyptic number.

21005259 is a deficient number, since it is larger than the sum of its proper divisors (10534965).

21005259 is a wasteful number, since it uses less digits than its factorization.

21005259 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20578.

The product of its (nonzero) digits is 900, while the sum is 24.

The square root of 21005259 is about 4583.1494629785. The cubic root of 21005259 is about 275.9154461639.

The spelling of 21005259 in words is "twenty-one million, five thousand, two hundred fifty-nine".

Divisors: 1 3 11 31 33 93 341 1023 20533 61599 225863 636523 677589 1909569 7001753 21005259