1668520111 has 2 divisors, whose sum is σ = 1668520112. Its totient is φ = 1668520110.

The previous prime is 1668520109. The next prime is 1668520153. The reversal of 1668520111 is 1110258661.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 1668520111 - 2¹ = 1668520109 is a prime.

It is a super-2 number, since 2×1668520111² = 5567918721622904642, which contains 22 as substring.

Together with 1668520109, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1668520181) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 834260055 + 834260056.

It is an arithmetic number, because the mean of its divisors is an integer number (834260056).

Almost surely, 2^1668520111 is an apocalyptic number.

1668520111 is a deficient number, since it is larger than the sum of its proper divisors (1).

1668520111 is an equidigital number, since it uses as much as digits as its factorization.

1668520111 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2880, while the sum is 31.

The square root of 1668520111 is about 40847.5227033415. The cubic root of 1668520111 is about 1186.0704389287.

Adding to 1668520111 its reverse (1110258661), we get a palindrome (2778778772).

The spelling of 1668520111 in words is "one billion, six hundred sixty-eight million, five hundred twenty thousand, one hundred eleven".