991358140 has 24 divisors (see below), whose sum is σ = 2087764560. Its totient is φ = 395417088.

The previous prime is 991358129. The next prime is 991358143. The reversal of 991358140 is 41853199.

It is a junction number, because it is equal to n+sod(n) for n = 991358093 and 991358102.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991358143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 63150 + ... + 77269.

It is an arithmetic number, because the mean of its divisors is an integer number (86990190).

Almost surely, 2^991358140 is an apocalyptic number.

It is an amenable number.

991358140 is an abundant number, since it is smaller than the sum of its proper divisors (1096406420).

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

991358140 is a wasteful number, since it uses less digits than its factorization.

991358140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 140781 (or 140779 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 40.

The square root of 991358140 is about 31485.8403095741. The cubic root of 991358140 is about 997.1110419586. Note that the first 3 decimals are identical.

The spelling of 991358140 in words is "nine hundred ninety-one million, three hundred fifty-eight thousand, one hundred forty".