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66666889 = 541123229
BaseRepresentation
bin1111111001010…
…0000110001001
311122110000210001
43332110012021
5114031320024
610340523001
71436442052
oct376240611
9148400701
1066666889
11346a4903
121a3b0461
1310a72683
148bd5729
155cbd244
hex3f94189

66666889 has 4 divisors (see below), whose sum is σ = 66790660. Its totient is φ = 66543120.

The previous prime is 66666881. The next prime is 66666913. The reversal of 66666889 is 98866666.

66666889 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98866666 = 249433333.

It can be written as a sum of positive squares in 2 ways, for example, as 50126400 + 16540489 = 7080^2 + 4067^2 .

It is a cyclic number.

It is not a de Polignac number, because 66666889 - 23 = 66666881 is a prime.

It is a Duffinian number.

It is a plaindrome in base 10.

It is not an unprimeable number, because it can be changed into a prime (66666881) 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, 61074 + ... + 62155.

It is an arithmetic number, because the mean of its divisors is an integer number (16697665).

Almost surely, 266666889 is an apocalyptic number.

It is an amenable number.

66666889 is a deficient number, since it is larger than the sum of its proper divisors (123771).

66666889 is a wasteful number, since it uses less digits than its factorization.

66666889 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123770.

The product of its digits is 4478976, while the sum is 55.

The square root of 66666889 is about 8164.9794243464. The cubic root of 66666889 is about 405.4805837965.

The spelling of 66666889 in words is "sixty-six million, six hundred sixty-six thousand, eight hundred eighty-nine".

Divisors: 1 541 123229 66666889