21208428184337 has 2 divisors, whose sum is σ = 21208428184338. Its totient is φ = 21208428184336.

The previous prime is 21208428184219. The next prime is 21208428184393. The reversal of 21208428184337 is 73348182480212.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20925144508801 + 283283675536 = 4574401^2 + 532244^2 .

It is a cyclic number.

It is not a de Polignac number, because 21208428184337 - 2¹² = 21208428180241 is a prime.

It is not a weakly prime, because it can be changed into another prime (21208428184637) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10604214092168 + 10604214092169.

It is an arithmetic number, because the mean of its divisors is an integer number (10604214092169).

Almost surely, 2^{21208428184337} is an apocalyptic number.

It is an amenable number.

21208428184337 is a deficient number, since it is larger than the sum of its proper divisors (1).

21208428184337 is an equidigital number, since it uses as much as digits as its factorization.

21208428184337 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4128768, while the sum is 53.

The spelling of 21208428184337 in words is "twenty-one trillion, two hundred eight billion, four hundred twenty-eight million, one hundred eighty-four thousand, three hundred thirty-seven".