991663139 has 2 divisors, whose sum is σ = 991663140. Its totient is φ = 991663138.

The previous prime is 991663121. The next prime is 991663157. The reversal of 991663139 is 931366199.

991663139 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (991663121) and next prime (991663157).

It is a cyclic number.

It is not a de Polignac number, because 991663139 - 2⁸ = 991662883 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 991663093 and 991663102.

It is not a weakly prime, because it can be changed into another prime (991663109) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 495831569 + 495831570.

It is an arithmetic number, because the mean of its divisors is an integer number (495831570).

Almost surely, 2^991663139 is an apocalyptic number.

991663139 is a deficient number, since it is larger than the sum of its proper divisors (1).

991663139 is an equidigital number, since it uses as much as digits as its factorization.

991663139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 236196, while the sum is 47.

The square root of 991663139 is about 31490.6833682599. The cubic root of 991663139 is about 997.2132877820.

The spelling of 991663139 in words is "nine hundred ninety-one million, six hundred sixty-three thousand, one hundred thirty-nine".