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20668909 = 293183277
BaseRepresentation
bin100111011011…
…0000111101101
31102220002102011
41032312013231
520242401114
62015001221
7340453132
oct116660755
942802364
1020668909
1110737948
126b09211
134388a31
142a60589
151c341c4
hex13b61ed

20668909 has 16 divisors (see below), whose sum is σ = 22417920. Its totient is φ = 19010880.

The previous prime is 20668891. The next prime is 20668913. The reversal of 20668909 is 90986602.

20668909 = 1552 + 1562 + ... + 4032.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20668909 - 29 = 20668397 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 (20668919) 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, 74479 + ... + 74755.

It is an arithmetic number, because the mean of its divisors is an integer number (1401120).

Almost surely, 220668909 is an apocalyptic number.

20668909 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

20668909 is a deficient number, since it is larger than the sum of its proper divisors (1749011).

20668909 is a wasteful number, since it uses less digits than its factorization.

20668909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 420.

The product of its (nonzero) digits is 46656, while the sum is 40.

The square root of 20668909 is about 4546.3071827583. The cubic root of 20668909 is about 274.4348016971.

The spelling of 20668909 in words is "twenty million, six hundred sixty-eight thousand, nine hundred nine".

Divisors: 1 29 31 83 277 899 2407 2573 8033 8587 22991 74617 249023 666739 712721 20668909