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128281889 = 5319312541
BaseRepresentation
bin1111010010101…
…10110100100001
322221101101200002
413221112310201
5230320010024
620421305345
73115243451
oct751266441
9287341602
10128281889
116645909a
1236b65255
1320766758
1413073d61
15b3de6ae
hex7a56d21

128281889 has 8 divisors (see below), whose sum is σ = 131389992. Its totient is φ = 125199360.

The previous prime is 128281883. The next prime is 128281891. The reversal of 128281889 is 988182821.

It can be written as a sum of positive squares in 4 ways, for example, as 38031889 + 90250000 = 6167^2 + 9500^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-128281889 is a prime.

It is a super-3 number, since 3×1282818893 (a number of 25 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (128281883) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3959 + ... + 16499.

It is an arithmetic number, because the mean of its divisors is an integer number (16423749).

Almost surely, 2128281889 is an apocalyptic number.

It is an amenable number.

128281889 is a deficient number, since it is larger than the sum of its proper divisors (3108103).

128281889 is a wasteful number, since it uses less digits than its factorization.

128281889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12787.

The product of its digits is 147456, while the sum is 47.

The square root of 128281889 is about 11326.1594991418. The cubic root of 128281889 is about 504.3381048402.

The spelling of 128281889 in words is "one hundred twenty-eight million, two hundred eighty-one thousand, eight hundred eighty-nine".

Divisors: 1 53 193 10229 12541 664673 2420413 128281889