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668138789 is a prime number
BaseRepresentation
bin100111110100101…
…111110100100101
31201120012222010002
4213310233310211
52332020420124
6150144311045
722362041333
oct4764576445
91646188102
10668138789
1131316861a
12167912485
13a85651c6
1464a42b53
153d9cc0ae
hex27d2fd25

668138789 has 2 divisors, whose sum is σ = 668138790. Its totient is φ = 668138788.

The previous prime is 668138771. The next prime is 668138803. The reversal of 668138789 is 987831866.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 606390625 + 61748164 = 24625^2 + 7858^2 .

It is a cyclic number.

It is not a de Polignac number, because 668138789 - 212 = 668134693 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (668138749) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 334069394 + 334069395.

It is an arithmetic number, because the mean of its divisors is an integer number (334069395).

Almost surely, 2668138789 is an apocalyptic number.

It is an amenable number.

668138789 is a deficient number, since it is larger than the sum of its proper divisors (1).

668138789 is an equidigital number, since it uses as much as digits as its factorization.

668138789 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3483648, while the sum is 56.

The square root of 668138789 is about 25848.3807810083. The cubic root of 668138789 is about 874.2230006784.

The spelling of 668138789 in words is "six hundred sixty-eight million, one hundred thirty-eight thousand, seven hundred eighty-nine".