123719891 has 2 divisors, whose sum is σ = 123719892. Its totient is φ = 123719890.

The previous prime is 123719881. The next prime is 123719899. The reversal of 123719891 is 198917321.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 123719891 - 2²² = 119525587 is a prime.

It is a super-2 number, since 2×123719891² = 30613222858103762, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (123719899) 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, 61859945 + 61859946.

It is an arithmetic number, because the mean of its divisors is an integer number (61859946).

Almost surely, 2^123719891 is an apocalyptic number.

123719891 is a deficient number, since it is larger than the sum of its proper divisors (1).

123719891 is an equidigital number, since it uses as much as digits as its factorization.

123719891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27216, while the sum is 41.

The square root of 123719891 is about 11122.9443494068. The cubic root of 123719891 is about 498.2873282089.

The spelling of 123719891 in words is "one hundred twenty-three million, seven hundred nineteen thousand, eight hundred ninety-one".