123877991 has 2 divisors, whose sum is σ = 123877992. Its totient is φ = 123877990.

The previous prime is 123877981. The next prime is 123878011. The reversal of 123877991 is 199778321.

It is a weak prime.

It is an emirp because it is prime and its reverse (199778321) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 123877991 - 2⁶ = 123877927 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (123877921) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 61938995 + 61938996.

It is an arithmetic number, because the mean of its divisors is an integer number (61938996).

Almost surely, 2^123877991 is an apocalyptic number.

123877991 is a deficient number, since it is larger than the sum of its proper divisors (1).

123877991 is an equidigital number, since it uses as much as digits as its factorization.

123877991 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 190512, while the sum is 47.

The square root of 123877991 is about 11130.0490115722. The cubic root of 123877991 is about 498.4994894407.

The spelling of 123877991 in words is "one hundred twenty-three million, eight hundred seventy-seven thousand, nine hundred ninety-one".