991518525 has 18 divisors (see below), whose sum is σ = 1775920250. Its totient is φ = 528809760.

The previous prime is 991518503. The next prime is 991518551. The reversal of 991518525 is 525815199.

It can be written as a sum of positive squares in 3 ways, for example, as 220789881 + 770728644 = 14859^2 + 27762^2 .

It is not a de Polignac number, because 991518525 - 2²¹ = 989421373 is a prime.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 2203150 + ... + 2203599.

Almost surely, 2^991518525 is an apocalyptic number.

It is an amenable number.

991518525 is a deficient number, since it is larger than the sum of its proper divisors (784401725).

991518525 is a wasteful number, since it uses less digits than its factorization.

991518525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4406765 (or 4406757 counting only the distinct ones).

The product of its digits is 162000, while the sum is 45.

The square root of 991518525 is about 31488.3871451048. The cubic root of 991518525 is about 997.1648109665.

The spelling of 991518525 in words is "nine hundred ninety-one million, five hundred eighteen thousand, five hundred twenty-five".