217384381909 has 2 divisors, whose sum is σ = 217384381910. Its totient is φ = 217384381908.

The previous prime is 217384381889. The next prime is 217384381919. The reversal of 217384381909 is 909183483712.

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., 145830806884 + 71553575025 = 381878^2 + 267495^2 .

It is a cyclic number.

It is not a de Polignac number, because 217384381909 - 2¹⁵ = 217384349141 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 217384381909.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217384381919) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108692190954 + 108692190955.

It is an arithmetic number, because the mean of its divisors is an integer number (108692190955).

Almost surely, 2^217384381909 is an apocalyptic number.

It is an amenable number.

217384381909 is a deficient number, since it is larger than the sum of its proper divisors (1).

217384381909 is an equidigital number, since it uses as much as digits as its factorization.

217384381909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2612736, while the sum is 55.

The spelling of 217384381909 in words is "two hundred seventeen billion, three hundred eighty-four million, three hundred eighty-one thousand, nine hundred nine".