217842554557 has 2 divisors, whose sum is σ = 217842554558. Its totient is φ = 217842554556.

The previous prime is 217842554497. The next prime is 217842554569. The reversal of 217842554557 is 755455248712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 208612341081 + 9230213476 = 456741^2 + 96074^2 .

It is a cyclic number.

It is not a de Polignac number, because 217842554557 - 2¹⁵ = 217842521789 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 217842554498 and 217842554507.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217842554257) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108921277278 + 108921277279.

It is an arithmetic number, because the mean of its divisors is an integer number (108921277279).

Almost surely, 2^217842554557 is an apocalyptic number.

It is an amenable number.

217842554557 is a deficient number, since it is larger than the sum of its proper divisors (1).

217842554557 is an equidigital number, since it uses as much as digits as its factorization.

217842554557 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15680000, while the sum is 55.

The spelling of 217842554557 in words is "two hundred seventeen billion, eight hundred forty-two million, five hundred fifty-four thousand, five hundred fifty-seven".