217990379 has 2 divisors, whose sum is σ = 217990380. Its totient is φ = 217990378.

The previous prime is 217990321. The next prime is 217990397. The reversal of 217990379 is 973099712.

Together with next prime (217990397) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 217990379 - 2¹⁶ = 217924843 is a prime.

It is not a weakly prime, because it can be changed into another prime (217990319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108995189 + 108995190.

It is an arithmetic number, because the mean of its divisors is an integer number (108995190).

Almost surely, 2^217990379 is an apocalyptic number.

217990379 is a deficient number, since it is larger than the sum of its proper divisors (1).

217990379 is an equidigital number, since it uses as much as digits as its factorization.

217990379 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 214326, while the sum is 47.

The square root of 217990379 is about 14764.4972484674. The cubic root of 217990379 is about 601.8373115859.

The spelling of 217990379 in words is "two hundred seventeen million, nine hundred ninety thousand, three hundred seventy-nine".