217031849 has 2 divisors, whose sum is σ = 217031850. Its totient is φ = 217031848.

The previous prime is 217031821. The next prime is 217031863. The reversal of 217031849 is 948130712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 217031824 + 25 = 14732^2 + 5^2 .

It is a cyclic number.

It is not a de Polignac number, because 217031849 - 2¹² = 217027753 is a prime.

It is not a weakly prime, because it can be changed into another prime (217531849) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108515924 + 108515925.

It is an arithmetic number, because the mean of its divisors is an integer number (108515925).

Almost surely, 2^217031849 is an apocalyptic number.

It is an amenable number.

217031849 is a deficient number, since it is larger than the sum of its proper divisors (1).

217031849 is an equidigital number, since it uses as much as digits as its factorization.

217031849 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 12096, while the sum is 35.

The square root of 217031849 is about 14732.0008484931. Note that the first 3 decimals coincide. The cubic root of 217031849 is about 600.9538984001.

The spelling of 217031849 in words is "two hundred seventeen million, thirty-one thousand, eight hundred forty-nine".