9781139 has 2 divisors, whose sum is σ = 9781140. Its totient is φ = 9781138.

The previous prime is 9781127. The next prime is 9781153. The reversal of 9781139 is 9311879.

9781139 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 9781139 - 2¹² = 9777043 is a prime.

It is not a weakly prime, because it can be changed into another prime (9781039) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4890569 + 4890570.

It is an arithmetic number, because the mean of its divisors is an integer number (4890570).

Almost surely, 2^9781139 is an apocalyptic number.

9781139 is a deficient number, since it is larger than the sum of its proper divisors (1).

9781139 is an equidigital number, since it uses as much as digits as its factorization.

9781139 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13608, while the sum is 38.

The square root of 9781139 is about 3127.4812549398. The cubic root of 9781139 is about 213.8601220009.

The spelling of 9781139 in words is "nine million, seven hundred eighty-one thousand, one hundred thirty-nine".