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68521421 = 531292857
BaseRepresentation
bin1000001010110…
…00110111001101
311202221020201102
410011120313031
5120020141141
610444352445
71461264623
oct405306715
9152836642
1068521421
1135751181
121ab45725
1311271827
149159513
15603799b
hex4158dcd

68521421 has 4 divisors (see below), whose sum is σ = 69814332. Its totient is φ = 67228512.

The previous prime is 68521417. The next prime is 68521423. The reversal of 68521421 is 12412586.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 50965321 + 17556100 = 7139^2 + 4190^2 .

It is a cyclic number.

It is not a de Polignac number, because 68521421 - 22 = 68521417 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 (68521423) 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 3 ways as a sum of consecutive naturals, for example, 646376 + ... + 646481.

It is an arithmetic number, because the mean of its divisors is an integer number (17453583).

Almost surely, 268521421 is an apocalyptic number.

It is an amenable number.

68521421 is a deficient number, since it is larger than the sum of its proper divisors (1292911).

68521421 is a wasteful number, since it uses less digits than its factorization.

68521421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1292910.

The product of its digits is 3840, while the sum is 29.

The square root of 68521421 is about 8277.7666674049. The cubic root of 68521421 is about 409.2061199650.

The spelling of 68521421 in words is "sixty-eight million, five hundred twenty-one thousand, four hundred twenty-one".

Divisors: 1 53 1292857 68521421