111781819 has 2 divisors, whose sum is σ = 111781820. Its totient is φ = 111781818.

The previous prime is 111781777. The next prime is 111781843. The reversal of 111781819 is 918187111.

It is a happy number.

It is a strong prime.

It is an emirp because it is prime and its reverse (918187111) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111781819 is a prime.

It is a super-2 number, since 2×111781819² = 24990350117897522, which contains 22 as substring.

It is a Chen prime.

It is equal to p_6399280 and since 111781819 and 6399280 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (111701819) 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, 55890909 + 55890910.

It is an arithmetic number, because the mean of its divisors is an integer number (55890910).

Almost surely, 2^111781819 is an apocalyptic number.

111781819 is a deficient number, since it is larger than the sum of its proper divisors (1).

111781819 is an equidigital number, since it uses as much as digits as its factorization.

111781819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 37.

The square root of 111781819 is about 10572.6921358753. The cubic root of 111781819 is about 481.7152450509.

The spelling of 111781819 in words is "one hundred eleven million, seven hundred eighty-one thousand, eight hundred nineteen".