217837928449 has 2 divisors, whose sum is σ = 217837928450. Its totient is φ = 217837928448.

The previous prime is 217837928381. The next prime is 217837928479. The reversal of 217837928449 is 944829738712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 174101735025 + 43736193424 = 417255^2 + 209132^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217837928449 is a prime.

It is not a weakly prime, because it can be changed into another prime (217837928479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108918964224 + 108918964225.

It is an arithmetic number, because the mean of its divisors is an integer number (108918964225).

Almost surely, 2^217837928449 is an apocalyptic number.

It is an amenable number.

217837928449 is a deficient number, since it is larger than the sum of its proper divisors (1).

217837928449 is an equidigital number, since it uses as much as digits as its factorization.

217837928449 is an evil number, because the sum of its binary digits is even.

The product of its digits is 48771072, while the sum is 64.

The spelling of 217837928449 in words is "two hundred seventeen billion, eight hundred thirty-seven million, nine hundred twenty-eight thousand, four hundred forty-nine".