991650 has 48 divisors (see below), whose sum is σ = 2687328. Its totient is φ = 240000.

The previous prime is 991643. The next prime is 991651. The reversal of 991650 is 56199.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (991651) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1350 + ... + 1950.

It is an arithmetic number, because the mean of its divisors is an integer number (55986).

2⁹⁹¹⁶⁵⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991650, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1343664).

991650 is an abundant number, since it is smaller than the sum of its proper divisors (1695678).

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

991650 is a wasteful number, since it uses less digits than its factorization.

991650 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 627 (or 622 counting only the distinct ones).

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 991650 is about 995.8162481101. The cubic root of 991650 is about 99.7208883584.

The spelling of 991650 in words is "nine hundred ninety-one thousand, six hundred fifty".