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20556517 is a prime number
BaseRepresentation
bin100111001101…
…0101011100101
31102200101020111
41032122223211
520230302032
62012333021
7336504352
oct116325345
942611214
1020556517
1110670463
126a74171
134349827
142a31629
151c10c47
hex139aae5

20556517 has 2 divisors, whose sum is σ = 20556518. Its totient is φ = 20556516.

The previous prime is 20556493. The next prime is 20556521. The reversal of 20556517 is 71565502.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14791716 + 5764801 = 3846^2 + 2401^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-20556517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20556017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10278258 + 10278259.

It is an arithmetic number, because the mean of its divisors is an integer number (10278259).

Almost surely, 220556517 is an apocalyptic number.

It is an amenable number.

20556517 is a deficient number, since it is larger than the sum of its proper divisors (1).

20556517 is an equidigital number, since it uses as much as digits as its factorization.

20556517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10500, while the sum is 31.

The square root of 20556517 is about 4533.9295318741. The cubic root of 20556517 is about 273.9364629703.

The spelling of 20556517 in words is "twenty million, five hundred fifty-six thousand, five hundred seventeen".