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21749117 = 132128693
BaseRepresentation
bin101001011110…
…1110101111101
31111220222011212
41102331311331
521031432432
62054054205
7352602335
oct122756575
944828155
1021749117
1111305485
12734a365
134676600
142c620c5
151d992b2
hex14bdd7d

21749117 has 6 divisors (see below), whose sum is σ = 23551002. Its totient is φ = 20075952.

The previous prime is 21749113. The next prime is 21749149. The reversal of 21749117 is 71194712.

It can be written as a sum of positive squares in 3 ways, for example, as 2292196 + 19456921 = 1514^2 + 4411^2 .

It is not a de Polignac number, because 21749117 - 22 = 21749113 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 (21749113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 64178 + ... + 64515.

It is an arithmetic number, because the mean of its divisors is an integer number (3925167).

Almost surely, 221749117 is an apocalyptic number.

It is an amenable number.

21749117 is a deficient number, since it is larger than the sum of its proper divisors (1801885).

21749117 is a wasteful number, since it uses less digits than its factorization.

21749117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128719 (or 128706 counting only the distinct ones).

The product of its digits is 3528, while the sum is 32.

The square root of 21749117 is about 4663.5948580467. The cubic root of 21749117 is about 279.1347310712.

The spelling of 21749117 in words is "twenty-one million, seven hundred forty-nine thousand, one hundred seventeen".

Divisors: 1 13 169 128693 1673009 21749117