991525 has 12 divisors (see below), whose sum is σ = 1302372. Its totient is φ = 746240.

The previous prime is 991511. The next prime is 991531. The reversal of 991525 is 525199.

It can be written as a sum of positive squares in 6 ways, for example, as 5476 + 986049 = 74^2 + 993^2 .

It is not a de Polignac number, because 991525 - 2⁵ = 991493 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 742 + ... + 1591.

It is an arithmetic number, because the mean of its divisors is an integer number (108531).

2⁹⁹¹⁵²⁵ is an apocalyptic number.

It is an amenable number.

991525 is a deficient number, since it is larger than the sum of its proper divisors (310847).

991525 is a wasteful number, since it uses less digits than its factorization.

991525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2360 (or 2355 counting only the distinct ones).

The product of its digits is 4050, while the sum is 31.

The square root of 991525 is about 995.7534835490. The cubic root of 991525 is about 99.7166981586.

It can be divided in two parts, 99 and 1525, that multiplied together give a triangular number (150975 = T₅₄₉).

The spelling of 991525 in words is "nine hundred ninety-one thousand, five hundred twenty-five".