9991566971136 has 351 divisors, whose sum is σ = 30026936813223. Its totient is φ = 3318232573440.

The previous prime is 9991566971077. The next prime is 9991566971179. The reversal of 9991566971136 is 6311796651999.

The square root of 9991566971136 is 3160944.

It is a perfect power (a square), and thus also a powerful number.

It is a Smith number, since the sum of its digits (72) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 38 ways as a sum of consecutive naturals, for example, 36869250681 + ... + 36869250951.

Almost surely, 2^{9991566971136} is an apocalyptic number.

9991566971136 is a gapful number since it is divisible by the number (96) formed by its first and last digit.

9991566971136 is the 3160944-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9991566971136

9991566971136 is an abundant number, since it is smaller than the sum of its proper divisors (20035369842087).

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

9991566971136 is an frugal number, since it uses more digits than its factorization.

9991566971136 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 594 (or 276 counting only the distinct ones).

The product of its digits is 148803480, while the sum is 72.

The spelling of 9991566971136 in words is "nine trillion, nine hundred ninety-one billion, five hundred sixty-six million, nine hundred seventy-one thousand, one hundred thirty-six".