139231691 has 2 divisors, whose sum is σ = 139231692. Its totient is φ = 139231690.

The previous prime is 139231679. The next prime is 139231693. The reversal of 139231691 is 196132931.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-139231691 is a prime.

Together with 139231693, 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 (139231693) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69615845 + 69615846.

It is an arithmetic number, because the mean of its divisors is an integer number (69615846).

Almost surely, 2^139231691 is an apocalyptic number.

139231691 is a deficient number, since it is larger than the sum of its proper divisors (1).

139231691 is an equidigital number, since it uses as much as digits as its factorization.

139231691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8748, while the sum is 35.

The square root of 139231691 is about 11799.6479184762. The cubic root of 139231691 is about 518.2978006152.

The spelling of 139231691 in words is "one hundred thirty-nine million, two hundred thirty-one thousand, six hundred ninety-one".