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68840209 = 82972
BaseRepresentation
bin1000001101001…
…10101100010001
311210112110000101
410012212230101
5120110341314
610455252401
71464063214
oct406465421
9153473011
1068840209
1135949739
121b07a101
1311353969
1491dd77b
15609c174
hex41a6b11

68840209 has 3 divisors (see below), whose sum is σ = 68848507. Its totient is φ = 68831912.

The previous prime is 68840201. The next prime is 68840257. The reversal of 68840209 is 90204886.

The square root of 68840209 is 8297.

It is a perfect power (a square), and thus also a powerful number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in only one way, i.e., 68310225 + 529984 = 8265^2 + 728^2 .

It is not a de Polignac number, because 68840209 - 23 = 68840201 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68840201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 4149 + ... + 12445.

Almost surely, 268840209 is an apocalyptic number.

68840209 is the 8297-th square number.

68840209 is the 4149-th centered octagonal number.

It is an amenable number.

68840209 is a deficient number, since it is larger than the sum of its proper divisors (8298).

68840209 is an frugal number, since it uses more digits than its factorization.

68840209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16594 (or 8297 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 37.

The cubic root of 68840209 is about 409.8397331172.

The spelling of 68840209 in words is "sixty-eight million, eight hundred forty thousand, two hundred nine".

Divisors: 1 8297 68840209