981778123 has 2 divisors, whose sum is σ = 981778124. Its totient is φ = 981778122.

The previous prime is 981778121. The next prime is 981778139. The reversal of 981778123 is 321877189.

It is a weak prime.

It is an emirp because it is prime and its reverse (321877189) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 981778123 - 2¹ = 981778121 is a prime.

Together with 981778121, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (981778121) 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, 490889061 + 490889062.

It is an arithmetic number, because the mean of its divisors is an integer number (490889062).

Almost surely, 2^981778123 is an apocalyptic number.

981778123 is a deficient number, since it is larger than the sum of its proper divisors (1).

981778123 is an equidigital number, since it uses as much as digits as its factorization.

981778123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 169344, while the sum is 46.

The square root of 981778123 is about 31333.3388421981. The cubic root of 981778123 is about 993.8887699462. Note that the first 3 decimals are identical.

The spelling of 981778123 in words is "nine hundred eighty-one million, seven hundred seventy-eight thousand, one hundred twenty-three".