91388136672 has 144 divisors (see below), whose sum is σ = 303918975360. Its totient is φ = 25503641856.

The previous prime is 91388136661. The next prime is 91388136691. The reversal of 91388136672 is 27663188319.

91388136672 is a `hidden beast` number, since 9 + 138 + 81 + 366 + 72 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 440422 + ... + 613797.

It is an arithmetic number, because the mean of its divisors is an integer number (2110548440).

Almost surely, 2^91388136672 is an apocalyptic number.

It is an amenable number.

91388136672 is an abundant number, since it is smaller than the sum of its proper divisors (212530838688).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

91388136672 is a wasteful number, since it uses less digits than its factorization.

91388136672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1054285 (or 1054274 counting only the distinct ones).

The product of its digits is 2612736, while the sum is 54.

The spelling of 91388136672 in words is "ninety-one billion, three hundred eighty-eight million, one hundred thirty-six thousand, six hundred seventy-two".