9991971121418 has 64 divisors (see below), whose sum is σ = 18181759647744. Its totient is φ = 4055962680000.

The previous prime is 9991971121393. The next prime is 9991971121501. The reversal of 9991971121418 is 8141211791999.

9991971121418 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (62).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 29292143 + ... + 29631293.

It is an arithmetic number, because the mean of its divisors is an integer number (284089994496).

Almost surely, 2^{9991971121418} is an apocalyptic number.

9991971121418 is a deficient number, since it is larger than the sum of its proper divisors (8189788526326).

9991971121418 is a wasteful number, since it uses less digits than its factorization.

9991971121418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 342531.

The product of its digits is 2939328, while the sum is 62.

The spelling of 9991971121418 in words is "nine trillion, nine hundred ninety-one billion, nine hundred seventy-one million, one hundred twenty-one thousand, four hundred eighteen".