991245500 has 72 divisors (see below), whose sum is σ = 2518392240. Its totient is φ = 339847200.

The previous prime is 991245499. The next prime is 991245509. The reversal of 991245500 is 5542199.

It is a Harshad number since it is a multiple of its sum of digits (35).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991245509) 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, 4271 + ... + 44729.

It is an arithmetic number, because the mean of its divisors is an integer number (34977670).

Almost surely, 2^991245500 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991245500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1259196120).

991245500 is an abundant number, since it is smaller than the sum of its proper divisors (1527146740).

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

991245500 is a wasteful number, since it uses less digits than its factorization.

991245500 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40492 (or 40473 counting only the distinct ones).

The product of its (nonzero) digits is 16200, while the sum is 35.

The square root of 991245500 is about 31484.0515181893. The cubic root of 991245500 is about 997.0732759763.

Adding to 991245500 its reverse (5542199), we get a palindrome (996787699).

The spelling of 991245500 in words is "nine hundred ninety-one million, two hundred forty-five thousand, five hundred".