991085850 has 36 divisors (see below), whose sum is σ = 2662718526. Its totient is φ = 264289440.

The previous prime is 991085833. The next prime is 991085857. The reversal of 991085850 is 58580199.

It can be written as a sum of positive squares in 3 ways, for example, as 876574449 + 114511401 = 29607^2 + 10701^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a junction number, because it is equal to n+sod(n) for n = 991085796 and 991085805.

It is not an unprimeable number, because it can be changed into a prime (991085857) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1100757 + ... + 1101656.

Almost surely, 2^991085850 is an apocalyptic number.

991085850 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

991085850 is an abundant number, since it is smaller than the sum of its proper divisors (1671632676).

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

991085850 is a wasteful number, since it uses less digits than its factorization.

991085850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2202431 (or 2202423 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 45.

The square root of 991085850 is about 31481.5160054277. The cubic root of 991085850 is about 997.0197435617.

The spelling of 991085850 in words is "nine hundred ninety-one million, eighty-five thousand, eight hundred fifty".