9991863774 has 24 divisors (see below), whose sum is σ = 21774183912. Its totient is φ = 3311368080.

The previous prime is 9991863769. The next prime is 9991863779. The reversal of 9991863774 is 4773681999.

It is an interprime number because it is at equal distance from previous prime (9991863769) and next prime (9991863779).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9991863779) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1601232 + ... + 1607459.

It is an arithmetic number, because the mean of its divisors is an integer number (907257663).

Almost surely, 2^9991863774 is an apocalyptic number.

9991863774 is an abundant number, since it is smaller than the sum of its proper divisors (11782320138).

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

9991863774 is a wasteful number, since it uses less digits than its factorization.

9991863774 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3208872 (or 3208869 counting only the distinct ones).

The product of its digits is 20575296, while the sum is 63.

The square root of 9991863774 is about 99959.3105918603. The cubic root of 9991863774 is about 2153.8502325759.

The spelling of 9991863774 in words is "nine billion, nine hundred ninety-one million, eight hundred sixty-three thousand, seven hundred seventy-four".