991825 has 12 divisors (see below), whose sum is σ = 1245580. Its totient is φ = 783360.

The previous prime is 991817. The next prime is 991867. The reversal of 991825 is 528199.

It can be written as a sum of positive squares in 6 ways, for example, as 5776 + 986049 = 76^2 + 993^2 .

It is not a de Polignac number, because 991825 - 2³ = 991817 is a prime.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

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, 2221 + ... + 2629.

2⁹⁹¹⁸²⁵ is an apocalyptic number.

It is an amenable number.

991825 is a deficient number, since it is larger than the sum of its proper divisors (253755).

991825 is a wasteful number, since it uses less digits than its factorization.

991825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 516 (or 511 counting only the distinct ones).

The product of its digits is 6480, while the sum is 34.

The square root of 991825 is about 995.9041118501. The cubic root of 991825 is about 99.7267540465.

The spelling of 991825 in words is "nine hundred ninety-one thousand, eight hundred twenty-five".