9991938 has 24 divisors (see below), whose sum is σ = 21967344.
Its totient is φ = 3027640.
The previous prime is 9991879. The next prime is 9991939. The reversal of 9991938 is 8391999.
It is not an unprimeable number, because it can be changed into a prime (9991939) 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, 6156 + ... + 7607.
It is an arithmetic number, because the mean of its divisors is an integer number (915306).
Almost surely, 29991938 is an apocalyptic number.
9991938 is an abundant number, since it is smaller than the sum of its proper divisors (11975406).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
9991938 is a wasteful number, since it uses less digits than its factorization.
9991938 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 13790 (or 13779 counting only the distinct ones).
The product of its digits is 157464, while the sum is 48.
The square root of 9991938 is about 3161.0026890213.
The cubic root of 9991938 is about 215.3855565958.
The spelling of 9991938 in words is "nine million, nine hundred ninety-one thousand, nine hundred thirty-eight".