217881423481 has 2 divisors, whose sum is σ = 217881423482. Its totient is φ = 217881423480.

The previous prime is 217881423433. The next prime is 217881423493. The reversal of 217881423481 is 184324188712.

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., 156704347881 + 61177075600 = 395859^2 + 247340^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217881423481 is a prime.

It is a super-2 number, since 2×217881423481² (a number of 23 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (217881433481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108940711740 + 108940711741.

It is an arithmetic number, because the mean of its divisors is an integer number (108940711741).

Almost surely, 2^217881423481 is an apocalyptic number.

It is an amenable number.

217881423481 is a deficient number, since it is larger than the sum of its proper divisors (1).

217881423481 is an equidigital number, since it uses as much as digits as its factorization.

217881423481 is an evil number, because the sum of its binary digits is even.

The product of its digits is 688128, while the sum is 49.

The spelling of 217881423481 in words is "two hundred seventeen billion, eight hundred eighty-one million, four hundred twenty-three thousand, four hundred eighty-one".