211028457581 has 2 divisors, whose sum is σ = 211028457582. Its totient is φ = 211028457580.

The previous prime is 211028457559. The next prime is 211028457617. The reversal of 211028457581 is 185754820112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 174298735081 + 36729722500 = 417491^2 + 191650^2 .

It is a cyclic number.

It is not a de Polignac number, because 211028457581 - 2⁶ = 211028457517 is a prime.

It is a super-2 number, since 2×211028457581² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (211028457511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105514228790 + 105514228791.

It is an arithmetic number, because the mean of its divisors is an integer number (105514228791).

Almost surely, 2^211028457581 is an apocalyptic number.

It is an amenable number.

211028457581 is a deficient number, since it is larger than the sum of its proper divisors (1).

211028457581 is an equidigital number, since it uses as much as digits as its factorization.

211028457581 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 179200, while the sum is 44.

The spelling of 211028457581 in words is "two hundred eleven billion, twenty-eight million, four hundred fifty-seven thousand, five hundred eighty-one".