9991851400771 has 4 divisors (see below), whose sum is σ = 9993253379472. Its totient is φ = 9990449422072.

The previous prime is 9991851400717. The next prime is 9991851400787. The reversal of 9991851400771 is 1770041581999.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-9991851400771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9991851404771) 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 in 3 ways as a sum of consecutive naturals, for example, 700978660 + ... + 700992913.

It is an arithmetic number, because the mean of its divisors is an integer number (2498313344868).

Almost surely, 2^{9991851400771} is an apocalyptic number.

9991851400771 is a deficient number, since it is larger than the sum of its proper divisors (1401978701).

9991851400771 is a wasteful number, since it uses less digits than its factorization.

9991851400771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1401978700.

The product of its (nonzero) digits is 5715360, while the sum is 61.

The spelling of 9991851400771 in words is "nine trillion, nine hundred ninety-one billion, eight hundred fifty-one million, four hundred thousand, seven hundred seventy-one".