217181129489 has 2 divisors, whose sum is σ = 217181129490. Its totient is φ = 217181129488.

The previous prime is 217181129467. The next prime is 217181129507. The reversal of 217181129489 is 984921181712.

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., 130344827089 + 86836302400 = 361033^2 + 294680^2 .

It is a cyclic number.

It is not a de Polignac number, because 217181129489 - 2³² = 212886162193 is a prime.

It is a super-2 number, since 2×217181129489² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 217181129489.

It is not a weakly prime, because it can be changed into another prime (217181120489) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108590564744 + 108590564745.

It is an arithmetic number, because the mean of its divisors is an integer number (108590564745).

Almost surely, 2^217181129489 is an apocalyptic number.

It is an amenable number.

217181129489 is a deficient number, since it is larger than the sum of its proper divisors (1).

217181129489 is an equidigital number, since it uses as much as digits as its factorization.

217181129489 is an evil number, because the sum of its binary digits is even.

The product of its digits is 580608, while the sum is 53.

The spelling of 217181129489 in words is "two hundred seventeen billion, one hundred eighty-one million, one hundred twenty-nine thousand, four hundred eighty-nine".