9991820789489 has 32 divisors (see below), whose sum is σ = 12480893061120. Its totient is φ = 7771116038400.

The previous prime is 9991820789453. The next prime is 9991820789549. The reversal of 9991820789489 is 9849870281999.

9991820789489 = T₁ + T₂ + ... + T₃₉₁₃₇.

9991820789489 is a nontrivial binomial coefficient, being equal to C(39139, 3).

It is not a de Polignac number, because 9991820789489 - 2¹² = 9991820785393 is a prime.

It is a super-2 number, since 2×9991820789489² (a number of 27 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (9991820780489) by changing a digit.

It is the 39137-th tetrahedral number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 255271082 + ... + 255310220.

It is an arithmetic number, because the mean of its divisors is an integer number (390027908160).

Almost surely, 2^{9991820789489} is an apocalyptic number.

It is an amenable number.

9991820789489 is a deficient number, since it is larger than the sum of its proper divisors (2489072271631).

9991820789489 is a wasteful number, since it uses less digits than its factorization.

9991820789489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45341.

The product of its (nonzero) digits is 1693052928, while the sum is 83.

The spelling of 9991820789489 in words is "nine trillion, nine hundred ninety-one billion, eight hundred twenty million, seven hundred eighty-nine thousand, four hundred eighty-nine".