981778139 has 2 divisors, whose sum is σ = 981778140. Its totient is φ = 981778138.

The previous prime is 981778123. The next prime is 981778141. The reversal of 981778139 is 931877189.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 981778139 - 2⁴ = 981778123 is a prime.

It is a Sophie Germain prime.

Together with 981778141, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (981778439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 490889069 + 490889070.

It is an arithmetic number, because the mean of its divisors is an integer number (490889070).

Almost surely, 2^981778139 is an apocalyptic number.

981778139 is a deficient number, since it is larger than the sum of its proper divisors (1).

981778139 is an equidigital number, since it uses as much as digits as its factorization.

981778139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 762048, while the sum is 53.

The square root of 981778139 is about 31333.3390975172. The cubic root of 981778139 is about 993.8887753453. Note that the first 3 decimals are identical.

The spelling of 981778139 in words is "nine hundred eighty-one million, seven hundred seventy-eight thousand, one hundred thirty-nine".