217920919 has 2 divisors, whose sum is σ = 217920920. Its totient is φ = 217920918.

The previous prime is 217920893. The next prime is 217920959. The reversal of 217920919 is 919029712.

It is a happy number.

It is an a-pointer prime, because the next prime (217920959) can be obtained adding 217920919 to its sum of digits (40).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 217920919 - 2¹⁹ = 217396631 is a prime.

It is a super-2 number, since 2×217920919² = 94979053875609122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (217920959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108960459 + 108960460.

It is an arithmetic number, because the mean of its divisors is an integer number (108960460).

Almost surely, 2^217920919 is an apocalyptic number.

217920919 is a deficient number, since it is larger than the sum of its proper divisors (1).

217920919 is an equidigital number, since it uses as much as digits as its factorization.

217920919 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 20412, while the sum is 40.

The square root of 217920919 is about 14762.1447967428. The cubic root of 217920919 is about 601.7733820665.

The spelling of 217920919 in words is "two hundred seventeen million, nine hundred twenty thousand, nine hundred nineteen".