991139609396 has 6 divisors (see below), whose sum is σ = 1734494316450. Its totient is φ = 495569804696.

The previous prime is 991139609389. The next prime is 991139609399. The reversal of 991139609396 is 693906931199.

It can be written as a sum of positive squares in only one way, i.e., 692789875600 + 298349733796 = 832340^2 + 546214^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991139609399) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 123892451171 + ... + 123892451178.

It is an arithmetic number, because the mean of its divisors is an integer number (289082386075).

Almost surely, 2^991139609396 is an apocalyptic number.

It is an amenable number.

991139609396 is a deficient number, since it is larger than the sum of its proper divisors (743354707054).

991139609396 is a wasteful number, since it uses less digits than its factorization.

991139609396 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 247784902353 (or 247784902351 counting only the distinct ones).

The product of its (nonzero) digits is 19131876, while the sum is 65.

The spelling of 991139609396 in words is "nine hundred ninety-one billion, one hundred thirty-nine million, six hundred nine thousand, three hundred ninety-six".